Cicadidae are almost confined to the warmer regions of the earth, but we

have one species, a great rarity, in the extreme south of England;

altogether there are about 800 species known. These Insects are seen above

ground—so far as the life-histories are at present known—only in the

perfect condition, the creatures in their earlier stages being subterranean

and living on roots. As soon as the individual comes out of the ground it

splits open the nymph-skin, and the perfect Cicada emerges. One species—the

North American _Cicada septendecim_—is a most notorious Insect owing to its

life-cycle of seventeen years. It is considered that the individual, after

nearly seventeen years of underground existence, comes to the surface and

lives for a brief period the life of a noisy Insect. This is the only

Insect at present known having so considerable a longevity. This fact, and

several other peculiarities, have attracted much attention, so that there

is an extensive literature connected with the seventeen-year Cicada. It has

a wide distribution over the United States, but does not confine its

appearance to every seventeenth year, being found somewhere or

other—frequently in numerous localities—almost every year. The evidence as

to its periodicity has been obtained by taking the locality and other

points into consideration as well as the year of appearance. {570}By so

doing it has been found possible to establish the existence of twenty-two

broods which are distinguished by consecutive numeration. This being done,

the evidence as to the years during which Cicadas have appeared in any

given locality is examined, and the result is believed to bear out the view

that the life-cycle of the individual Insect is really one of seventeen

years. According to this view there are, underground, in certain localities

individuals of different ages that will appear on the surface as mature

individuals in different years. Thus in 1885 it was understood that there

were underground in Alabama two broods, viz. brood xviii. that would appear

on the surface in 1894, and brood iv. that would appear on the surface in

1896. The predictions made as to the years in which Cicadas would appear in

some given locality are considered to have proved correct. Moreover,

particular entomologists have in certain localities verified by personal

examination the appearance of the Insects for several consecutive periods

of seventeen years. These facts appear fairly conclusive, but they are much

complicated by another point, viz. that in certain localities the period is

one of thirteen, not of seventeen, years. This is to some extent a question

of climate, the thirteen-year interval being chiefly characteristic of the

Southern States. It is not, however, entirely so, for there are localities

in which the broods have an interval of either thirteen years or seventeen

years. Another fact should be remembered, viz. that it is admitted that not

quite all the individuals of a particular brood are true to their proper

time of appearance; in other words, a few specimens may appear precociously

a year or two before their comrades, while some may lag behind to a

considerable extent. It is therefore a matter for great surprise that,

under these circumstances, the broods should keep distinct at all, for one

would suppose that time-variation of this kind would lead to completely

obscuring the distinctness of the broods. We must also call attention to

the fact that both the seventeen-year and the thirteen-year broods have a

dimorphic form, or sub-species, called _C. cassinii_ which accompanies the

ordinary form, with which it is apparently as a rule not connected by

intermediates.[502]

{571}Cicadidae are provided with powerful ovipositors. The eggs of _C.

septendecim_ are deposited in the woody stems of bushes; after remaining

there a few weeks the young hatch out, drop to the ground, and, as

previously stated, disappear for nearly seventeen years, nearly the whole

of which time is passed in the larval state, the nymph-condition existing

for only a few days. They feed on the roots of various trees; it has been

said that they are injurious in this way, but other authorities maintain

that they suck only a moist exudation from the roots. It is very difficult

to obtain information as to their strange, prolonged, subterranean life; it

said that the Insects sometimes penetrate to a great depth—ten feet, even

twenty feet are mentioned;—and as great changes may take place on the

surface during their long lives, these Insect Rip Van Winkles sometimes

emerge in very strange conditions, and may appear even in deep cellars.

When the pupa comes to the surface it hooks itself on to the stem of some

plant or other object, the skin of the back splits, and the Cicada emerges.

Among the inexplicable peculiarities of this Insect must be mentioned the

fact that when emerging it sometimes constructs chimneys, or flues,

extending several inches above the surface of the ground. The reason for

this is much disputed; it was said that they are for refuge against

inundations, but this appears to be very doubtful. Certain of the broods

consist of an almost incalculable number of individuals, and it is very

strange to hear woods, or other localities, that have been for many years

free from these Insects, all at once resounding with their noisy song. The

seventeen-year Cicada is considered to be doomed to a speedy extinction;

the extension of cultivation and building, and the introduction to America

of the English sparrow, are likely to prove too much for the Insect.

Although Hemiptera are classified by many among the Ametabola or Insects

without metamorphosis, it is impossible to deny that the Cicadidae exhibit

a considerable amount of metamorphosis, and they are usually mentioned as

exceptional. The young (Fig. 280, A) is totally unlike the adult in form

and colour, and maintains, to a certain extent, its existence by the aid of

a different set of implements. The larva of the Cicada is colourless, with

an integument of very feeble consistence, rather large antennae, and a

remarkable pair of fossorial legs; {572}the wings are totally wanting. The

mode of passage from the larval to the pupal state has not been recorded.

The pupa, or nymph, differs from the larva by its much shorter, compressed

form; by being encased in a remarkably hard shell; and by the antennae

approximating in form to those of the adult. It has short wing-pads at the

sides of the body; the front legs are remarkably powerful, and the creature

is capable of moving about; the imago escapes from the pupa by the

splitting dorsally of the middle of the thoracic segments. The empty

pupa-skin does not shrivel, but retains its form, and in countries where

Cicadas occur, frequently attracts attention by the strange form it

presents, being often placed in a conspicuous position.

SONG.—Cicadas are the most noisy of the Insect world; the shrilling of

grasshoppers and even of crickets being insignificant in comparison with

the voice of Cicada. Darwin heard them in South America when the _Beagle_

was anchored a quarter of a mile from the shore; and _Tympanoterpes gigas_,

from the same region, is said to make a noise equal to the whistle of a

locomotive.[503] A curious difference of opinion prevails as to whether

their song is agreeable or not; in some countries they are kept in cages,

while in others they are considered a nuisance. The Greeks are said to have

decided in favour of their performances, the Latins against them. Only the

males sing, the females being completely dumb; this has given rise to a

saying by a Greek poet (so often repeated that it bids fair to become

immortal) "Happy the Cicadas' lives, for they all have voiceless

wives."[504] The writer considers the songs of the European species he has

heard far from unpleasant, but he is an entomologist, and therefore

favourably prepossessed; and he admits that Riley's description of the

performances of the seventeen-year Cicada is far from a satisfactory

testimonial to the good taste of that Insect; Riley says, "The general

noise, on approaching the infested woods, is a combination of that of a

distant threshing-machine and a distant frog-pond. That which they make

when disturbed, mimics a nest of young snakes or young birds under similar

circumstances—a sort of scream. They can also produce {573}a chirp somewhat

like that of a cricket and a very loud, shrill screech prolonged for

fifteen or twenty seconds, and gradually increasing in force and then

decreasing." The object, or use of the noise is very doubtful; it is said

that it attracts the females to the males. "De gustibus non est

disputandum!" perhaps, however, there may be some tender notes that we fail

to perceive; and it may be that the absence of any definite organs of

hearing reduces the result of a steam-engine whistle to the equivalent of

an agreeable whisper. No special auditory organs have been detected[505] as

we have already intimated; and certain naturalists, amongst whom we may

mention Giard, think that the Insects do not hear in our sense of the word,

but feel rhythmical vibrations; it is also recorded that though very shy

the Insects may be induced to approach any one who will stand still and

clap his hands—in good measure—within the range of their sensibilities.

There is a good deal of support to the idea that the males sing in rivalry.

VOCAL STRUCTURES.—Although we may not be able to pronounce a final opinion

as to the value to the Insect of the sounds, yet we cannot withhold our

admiration from the structures from which they proceed. These are indeed so

complex that they must be ranked as amongst the most remarkable

voice-organs in the animal kingdom. They are totally different from the

stridulating organs that are found in many other Insects, and are indeed

quite peculiar to the Cicadidae. Some difference of opinion has existed as

to the manner in which the structures act, but the account given by Carlet,

some of whose figures we reproduce, will, we believe, be found to be

essentially correct. The structures are partly thoracic and partly

abdominal. On examining a male _Cicada_ there will be seen on the under

surface two plates—the opercula—usually meeting in the middle line of the

body and overlapping the base of the abdomen to a greater or less extent

according to the species, sometimes nearly covering this part of the body;

these are enlargements of the metathoracic epimera; they can be slightly

moved away from the abdomen, and, as the latter part is capable of a still

greater extent of movement, a wide fissure may be produced, displaying the

complex {574}structures. In order to see the parts it is better to cut away

an operculum; underneath it three membranes can be seen, an external, the

timbal; an anterior, the folded or soft membrane; and a posterior, the

mirror. This last is a most beautiful object, tensely stretched and

pellucid, yet reflecting light so as to be of varied colours; there are

also three stigmata, and some chambers connected with the apparatus. The

sound is primarily produced by the vibrations of the timbal, to which a

muscle is attached; the other membranes are probably also thrown into a

condition of vibration, and the whole skeleton of the Insect helps to

increase or modify the sound, which is probably also influenced by the

position of the opercula. The stigmata probably play an important part by

regulating the tension of the air in the chambers. In the female some of

the structures are present in a rudimentary form, but there are no muscles,

and this sex appears to be really quite voiceless.

[Illustration: Fig. 281.—Musical apparatus of _Cicada plebeia_. (After

Carlet.) A, Ventral view (Operculum on right side is removed); _ap_,

apophysis; C, cavern; _c_, trochantin (cheville of Réaumur); _ent_, part of

internal skeleton of abdomen; _mi_, specular membrane; _m.pl_, soft or

folded membrane; P, base of leg; _st_, _st′_, _st″_, stigmata; _t_, drum

"timbale"; _v_, operculum; _1a_, first, _2a_, second abdominal segment: B,

same seen laterally, portion of abdominal wall as well as operculum

removed; A, point of insertion of hind wing; _Mes_, mesothorax; _sc_,

scutum of metathorax; _3a_, third abdominal segment; rest as in A.]

FAM. 2. FULGORIDAE.—_Ocelli two (rarely three, or entirely obsolete),

placed beneath the eyes or near the eyes, usually in cavities of the

cheeks, antennae placed beneath the eyes, very variable in form; usually of

two joints terminated by a very fine hair, the second joint with a peculiar

texture of the surface, owing to the existence of sensitive structures_

(Hansen). _Form of head very diverse; vertex and face forming either a

continuous curve, or the planes of the vertex and face forming an acute

angle, or both {575}prolonged so as to form a projection or growth that may

be monstrous. Prothorax neither armed nor unusually developed._

[Illustration: Fig. 282—_Fulgora candelaria._ × 1. China.]

This family is of large extent, and includes at present so great a variety

of forms that it is really almost impossible to frame a definition that

will apply to all. The unusual situation of the ocelli and the peculiar

second joint of the antennae must at present be taken as the best

diagnostic characters: occasionally a third ocellus is present. Some of the

Fulgoridae are amongst the largest Insects, others are quite small. The

family includes the so-called Lantern-flies, in which the front of the head

forms a huge misshapen proboscis that was formerly believed to be luminous.

Many of the species are of brilliant or beautiful coloration. A great

many—and of very different kinds—have the curious power of excreting large

quantities of a white, flocculent wax. This is exhibited by our little

British Insects of the genus _Cixius_, and in some of the exotic forms is

carried to an extent that becomes a biological puzzle. The Tropical

American genus _Phenax_ may be cited as an example; being about an inch

long it flies about with a large mass of this waxy substance twice as long

as itself; indeed, in the Mexican _P. auricoma_, the waxy processes are

four or five inches long. This wax forms a favourite food of certain kinds

of Lepidoptera, and two or three larvae of a maggot-like nature may

frequently be found concealed in the wax of the live Fulgorids; this has

been recorded by Westwood as occurring in India; and Champion has observed

it in the New World.[506] {576}The wax of Fulgorids is used by the Chinese

for candles and other purposes; and this white Insect-wax is said to be

much esteemed in India. Very curious chemical substances have been obtained

from it, but its importance in the economy of the Insects that produce it

is quite obscure. We have about seventy species of Fulgoridae in Britain.

They belong to the subfamilies Tettigometrides, Issides, Cixiides, and

Delphacides, which by many authors are treated as separate families. The

exotic subfamily Flatides is highly peculiar. In some of its members the

head is very different from that of the ordinary forms, being narrow, and

the vertex and front forming a continuous curve. Some of these Insects are

remarkably like butterflies or moths (_e.g._ the African _Ityraea

nigrocincta_ and the species of the genus _Pochazia_), but the young are

totally unlike the old, the posterior part of the body bearing a large bush

of curled, waxy projections, several times the size of the rest of the

body.

[Illustration: Fig. 283—A, B, _Heteronotus trinodosus_. A, Male seen from

above; B, profile of female; _a_, terminal part of pronotum; _b_, terminal

part of abdomen: C, front view of head and pronotum of _Cyphonia clavata_.

Both species from Central America. (From _Biol. Centr. Amer. Rhynch.

Homopt._ II.)]

FAM. 3. MEMBRACIDAE.—_Prothorax prolonged backwards into a hood or

processes of diverse forms; antennae inserted in front of the eyes; ocelli

two, placed between the two eyes._—This family is of large extent but its

members are chiefly tropical, and are specially abundant in America.

Although not of large size the Membracidae are unsurpassed for the variety

and grotesqueness of their shapes, due to the unusual development of the

pronotum. We figure two of these forms (Fig. 283).[507] Very little is

known about their {577}habits and life-histories. We have only two species

of the family in Britain, and these do not afford any ground for supposing

that there are any peculiarities in their lives at all commensurate with

the oddness of the Insect's structures. Belt has recorded the fact that in

Nicaragua the larvae of certain Homoptera were assiduously attended by ants

for the sake of a sweet juice excreted by the bugs, but it is by no means

clear that these larvae were really those of Membracidae. In North America

_Ceresa bubalus_ and _C. taurina_ place their eggs in an extremely neat

manner in the woody twigs of trees. The young have but little resemblance

to the adults, the great thoracic hood being absent, while on the back

there is on each segment a pair of long, sub-erect processes having

fringed, or minutely spiny, margins.[508]

FAM. 4. CERCOPIDAE.—_Ocelli two (occasionally absent) placed on the vertex;

antennae placed between the eyes. Thorax not peculiarly formed._—In the

characteristic forms of this family the front of the vertex bears a suture,

touched on each side by one at right angles to it, or converging to it so

as to form a triangle or a sort of embrasure; the hind tibiae have only one

to three strong spines. The Cercopidae are much less extraordinary than

many of the previously considered families. But some of them have the habit

of secreting a large quantity of fluid; and when in the immature stages,

certain of them have the art of emitting the liquid in the form of bubbles

which accumulate round the Insect and conceal it. These accumulations of

fluid are called cuckoo-spits or frog-spits; and the perfect Insects are

known as frog-hoppers, their power of leaping being very great. The most

abundant of the frog-hoppers in our gardens is _Philaenus spumarius_, a

little Insect of about a quarter of an inch long, obscurely coloured, with

more or less definite pale spots; it is so variable in colour that it has

received scores of names. Some of the Insects do not use their fluid in

this manner, but eject it in the form of drops, and sometimes cast them to

a considerable distance. The phenomena known as weeping-trees are due to

Cercopidae; some of the species make such copious exudations of this kind

that the drops have been compared to a shower of rain. In Madagascar it is

said that _Ptyelus goudoti_ exudes so much fluid that five or six dozen

larvae would about fill a {578}quart vessel in an hour and a half. The

frog-spit is considered by some naturalists to be a protective device; the

larvae are, however, a favourite food with certain Hymenoptera, which pick

out the larvae from the spits and carry them off to be used as stores of

provision for their larvae. In Ceylon the larva of _Machaerota guttigera_

constructs tubes fixed to the twigs of the tulip-tree, and from the tube

water is exuded drop by drop. According to Westwood, this Insect is

intermediate between Cercopidae and Membracidae.[509]

FAM. 5. JASSIDAE.—_Ocelli two, placed just on the front margin of the head

(almost in a line with the front of the eyes or more to the front) or on

the deflexed frons. Hind tibiae usually with many spines._ This vaguely

limited family includes a very large number of small or minute Insects,

usually of narrow, parallel form, and frequently excessively delicate and

fragile. They are often mentioned under the name of Cicadellinae. Ashmead

distinguishes two families, Bythoscopidae, in which the ocelli are clearly

on the frons or front, and Jassidae, in which they are on the upper edge

thereof. _Ulopa_, _Ledra_, and a few other exceptional forms, are also by

many distinguished as representatives of distinct families. Very little is

actually known as to the life-histories of these small and fragile Insects,

but it is believed that the eggs are usually deposited in the leaves or

stems of plants, and more particularly of grasses. In North America the

development of _Deltocephalus inimicus_, from hatching to assumption of the

adult form, has been observed by Webster to occupy about six weeks. As

Jassidae are numerous both in species and individuals it is believed that

they consume a considerable part of the vegetation of pastures. Osborn has

calculated that on an acre of pasture there exist, as a rule, about one

million of these hoppers, and he considers they obtain quite as large a

share of the food as the Vertebrates feeding with them.

FAM. 6. PSYLLIDAE.—_Minute Insects with wings usually transparent, placed

in a roof-like manner over the body; with three ocelli, and rather long,

thin antennae of eight to ten joints. Tarsi two-jointed._—These small

Insects have been studied chiefly in Europe and North America, very little

information having yet been obtained as to the exotic forms. They are about

the {579}size of Aphidae, but in form and general appearance remind one

rather of Cicadidae. The wings are in many cases even more perfectly

transparent than they are in many Cicadidae. They are sometimes called

springing plant-lice, as their habit of jumping distinguishes them from the

Aphidae. Löw has called attention to the remarkable variation in colour

they present in conformity with either the age of the individual, the

food-plant, the climate, and, more particularly, the season of the

year.[510] Réaumur long since pointed out that at their ecdyses these

Insects go through a remarkable series of changes of colour, and Löw found

that this did not take place in the normal manner in the winter generation

that hibernates. This has been confirmed by Slingerland in North America in

the case of _Psylla pyricola_,[511] which has been introduced there. He

finds that there are several generations in the year, and that the

hibernating adults differ from the summer adults in size, being nearly

one-third larger; in their much darker colouring; and especially in the

coloration of the front wings.

[Illustration: Fig. 284—_Psylla succincta._ x 15. Europe. (After Heeger.)

A, larva before first moult. B, larva after third moult. C, adult.]

In the earlier stages, Psyllidae differ greatly in appearance from the

adult forms; the legs and antennae in the newly hatched larvae are short,

and have a less number of joints. In the nymph the shape is very peculiar,

the large wing-pads standing out horizontally {580}from the sides of the

body, so that the width of the creature is about as great as the length.

The period occupied by the development apparently varies according to

season. Witlaczil, who has given an account of many details of the anatomy

and histology of various Psyllidae,[512] considers that there are four

larval stages; Heeger's account of _Psylla succincta_ is not quite clear on

this point, and Slingerland indicates a stage more than this, the perfect

Insect being disclosed as the result of a fifth moult; it is probable that

he is correct. In these earlier stages the body bears long hairs called

wax-hairs; according to Witlaczil in the young larvae of certain

species—_Trioza rhamni_, e.g.—these are broad and flat, so as to make the

body appear studded with oval processes; he states that these hairs change

their form during the growth of the individual. Nothing is more remarkable

in Psyllidae than the amount of matter they secrete or exude from their

bodies; in some species the substance is a "honey-dew," and the nymph may

keep itself covered with a drop of it: in other cases it is solid, as shown

in Réaumur's figures of _P. buxi_, where this exudation forms a string

several times longer than the body, and attached to it. Another form of

exudation is a light downy or waxy matter. Slingerland says that honey-dew

was exuded by _P. pyricola_ in such quantities that it "literally rained

from the trees upon the vegetation beneath; in cultivating the orchard the

back of the horse and the harness often became covered with the sticky

substance dropping from the trees. It attracts thousands of ants, bees, and

wasps, which feed upon it." The writer last year observed in the New Forest

a stunted sloe-bush, about which a large number of Bombi were busily

occupied; and examination showed that they were thrusting their proboscides

into the curled and deformed leaves, in which were secreted nymphs of a

_Psylla_ exuding honey-dew. It must not be assumed that this honey-dew is

the excrement of the Insect; this also is known, and is a different

substance. Those who have tasted it say that the honey-dew has a clean,

good flavour. The source of the honey-dew is not quite certain, but it

seems probable that it comes, like the solid matter figured by Réaumur,

directly from the alimentary canal, and not from hairs or pores on the

body. Psyllidae give rise to definite formations or galls on certain

plants; sometimes these Psyllid galls are mere changes in form of a limited

part, or {581}parts, of a leaf, giving rise either to crumpling or to

growth of a portion in one direction only, so that on one surface of the

leaf a swelling is formed, and on the opposite side a more or less deep

cavity in which the Insect dwells. A formation of this kind on the leaves

of _Aegopodium podagraria_ is described by Thomas[513] who states that the

growth is due to the deposition of an egg of the _Psylla_, and is

independent of the after life of the Insect; a fungus—_Puccinia

aegopodii_—forms similar structures on the leaves. Structures much more

definite than this may be the result of the attacks of Psyllidae; for an

example the reader may refer to Réaumur's account of _Psylla buxi_.[514] In

Australia and Tasmania there are Psyllidae known as Laap or Lerp Insects,

the products of which are called leaf-manna or Lerp, and are used as food.

This manna is a scale produced by the young Insect on the leaves of

_Eucalyptus_ as a covering or protection. The scale is fastened to the leaf

by a hinge, and is somewhat like the shell of a cockle. Although the scales

are said to be in some cases objects of great beauty, very little is known

about these Australian Psyllidae, one of which has, however, been referred

by Schwarz to the genus _Spondyliaspis_, Signoret.[515] About 160 species

of Psyllidae are known to occur in the Palaearctic region, and about fifty

of them have been found in Britain.[516]

FAM. 7. APHIDAE (_Plant-lice or Green-fly._)—_Minute Insects; as usually

met with destitute of wings, though many individuals have two pairs of

transparent wings. Antennae long, or moderately long, three- to

seven-jointed; abdomen frequently with a pair of tubes (siphons), or short

processes on the upper side of the fifth abdominal segment. Tarsi

two-jointed, first joint sometimes excessively short._—These soft-skinned

Insects are frequently called blight, and are so abundant in temperate

climates that a garden, however small, is sure to afford abundance of

specimens during the warm months of the year. This great abundance is due

to peculiarities in the physiological processes that render these obscure

little animals highly important creatures; the individual life for several

generations is restricted to constant, or at any rate copious, imbibition

of food, accompanied by an almost uninterrupted {582}production of young by

parthenogenetic females, the young so produced becoming rapidly (sometimes

in the course of eight or ten days, but more usually in about twenty days)

themselves devoted to a similar process; so that in the comparatively short

period of a few months the progeny resulting from a single individual is

almost innumerable. This remarkable state of affairs is accompanied by

other peculiarities of physiology, with the result that the life-histories

of successive generations become very diverse, and complex cycles of series

of generations differing more or less from one another are passed through,

the species finally returning to bi-sexual reproduction, and thus

inaugurating another cycle of generations. The surprising nature of these

facts has in the last 150 years caused an immense amount of discussion, but

no satisfactory light has yet been thrown on the conditions that really

give rise to the exceptional phenomena. These phenomena are (1)

parthenogenesis; (2) oviparous and viviparous reproduction; (3) the

production of generations of individuals in which the sexes are very

unequally represented, males being frequently entirely absent; (4) the

production of individuals differing as to the acquirement of wings, some

remaining entirely apterous, while others go on to the winged form; (5) the

production of individuals of the same sex with different sexual organs, and

distinctions in the very early (but not the earliest) stages of the

formation of the individual; (6) differences in the life-habits of

successive generations; (7) differences in the habits of individuals of one

generation, giving rise to the phenomenon of parallel series. All these

phenomena may occur in the case of a single species, though in a very

variable extent.

The simple form of Aphid life may be described as follows:—eggs are laid in

the autumn, and hatch in the spring, giving rise to females of an imperfect

character having no wings; these produce living young parthenogenetically,

and this process may be repeated for a few or for many generations, and

there may be in these generations a greater or less number of winged

individuals, and perhaps a few males.[517] After a time when temperature

falls, {583}or when the supply of food is less in quantity, or after a

period of deliberate abstention from food, sexual individuals are produced

and fertilised eggs are laid which hatch in the spring, and the phenomena

are repeated. In other cases these phenomena are added to or rendered more

complicated by the intercalated parthenogenetic generations exhibiting

well-marked metamorphosis, of kinds such as occur in apterous or in winged

Insects; while again the habits of successive generations may differ

greatly, the individuals of some generations dwelling in galls, while those

of other generations live underground on roots.

PARTHENOGENESIS.—Returning to the various kinds of peculiarities we have

enumerated on the preceding page, we may remark that the phenomena of

parthenogenesis have been thoroughly established as occurring in Aphidae

since Bonnet discovered the fact 150 years ago; and though they have not

been investigated in much detail it is known that the parthenogenesis is

usually accompanied by the production of young all of the female sex. In

other cases males are parthenogenetically produced; but whether these males

come from a female that produces only that sex is not yet, so far as the

writer knows, established. A note by Lichtenstein[518] suggests that

usually only one sex is produced by a parthenogenetic female, but that both

sexes are sometimes so produced. There is not at present any species of

Aphid known to be perpetuated by an uninterrupted series of parthenogenetic

generations. It was formerly supposed that there are no males at all in

_Chermes_, but, as we shall subsequently show, this was erroneous. It has,

however, been observed that a series of such generations may be continued

without interruption for a period of four years, and we have no reason to

suppose that even this could not be much exceeded under favourable

conditions. The parthenogenetic young may be produced either viviparously

or oviparously, according to species.

OVIPAROUS AND VIVIPAROUS REPRODUCTION.—The distinction between these two

processes has been extensively discussed, some naturalists maintaining that

they are thoroughly distinct _ab initio_. This view, however, cannot be

sustained. The best {584}authorities are agreed that in the earliest

processes of individualisation the ovum, and the pseudovum[519] giving rise

to a viviparous individual, are indistinguishable. Leydig, Huxley,

Balbiani, and Lemoine are agreed as to this. Nevertheless, differences in

the development occur extremely early. The nature of these differences may

be briefly described by saying that in the viviparous forms the embryonic

development sets in before the formation of the egg is properly completed.

Balbiani says, "In fact at this moment [when the viviparous development is

commencing] the germ [pseudovum] is far from having obtained the

development it is capable of, and from having accumulated all the matter

necessary for the increase of the embryo, so that the evolution of the

former coincides, so to speak, with that of the latter. On the other hand,

in the true ovum the two processes are chronologically separate, for the

rudiment of the new individual never appears before the egg has completed

the growth of its constituent parts."[520] As regards the difference in

structure of the organs of viviparously and oviparously producing

individuals, it is sufficient to remark that they are not of great

importance, being apparently confined to certain parts remaining

rudimentary in the former. Leydig, indeed, found an _Aphis_ in which

certain of the egg-tubes contained eggs in various stages of development,

and others embryos in all stages.[521]

As regards the physiology of production of winged and wingless individuals

there has been but little exact inquiry. Vast numbers of individuals may be

produced without any winged forms occurring, while on the other hand these

latter are occasionally so abundant as to float about in swarms that darken

the air; the two forms are probably, however, determined by the supply of

food. The winged forms are less prolific than the apterous forms; and

Forbes has noticed in _Aphis maidi-radicis_, where the generations consist

partly of apterous and partly of winged individuals, that when the corn

begins to flag in consequence of the attacks of the _Aphis_, then the

proportion of {585}winged individuals becomes large.[522] The appearance of

winged individuals is frequently accompanied by a peculiar change of habit;

the winged individuals migrating to another plant, which in many cases is

of a totally different botanical nature from that on which the apterous

broods were reared: for instance _Aphis mali_, after producing several

apterous generations on apple, gives rise to winged individuals that

migrate to the stems of corn or grass, and feeding thereon commence another

cycle of generations. The study of this sort of Aphis-migration is chiefly

modern, but many very curious facts have already been brought to light;

thus _Drepanosiphum platanoides_, after producing a certain number of

viviparous generations on maple (_Acer_), quits this food-plant for

another, but after two or three months returns again to the maple, and

produces sexual young that lay eggs.[523] Histories such as this are rather

common. Even more interesting are the cases of those species that, after

some weeks of physiological activity on a plant, pass into a state of

repose on the same plant, and then after some weeks produce sexual young.

On the whole, it would appear that the appearance of winged forms is a

concomitant of decreasing nutrition. It is a very remarkable fact that the

sexually perfect females are invariably apterous, and this is frequently

also the case with the males. It is also highly remarkable that the

sexually perfect individuals are of comparatively small size. There are at

least three kinds of males in Aphidae—1, winged males; 2, wingless males

with mouth well developed; 3, wingless small males with mouth absent. As

regards some of these points the conditions usual in Insect life are

reversed.[524] Huxley inclined to treat all these products of a fertilised

egg, that are antecedent to another process of gamogenesis (_i.e._

production with fertilisation), as one zoological individual: in that case

the Aphis zoological individual is winged before attaining the mature

state, and is wingless and smaller when mature. Some species may have as a

rule two, others three, winged generations in a year.

{586}[Illustration: Fig. 285—_Chermes abietis_; hibernating female or

"winter-mother." Europe. Much magnified. (After Cholodkovsky.)]

PARALLEL SERIES.—In certain cases individuals of one generation assume

different habits, and so set up the phenomenon known as parallel series.

This has been recently investigated in the genus _Chermes_ by Blochmann,

Dreyfus, and Cholodkovsky. This latter savant informs us[525] that a

wingless parthenogenetic female of _Chermes_ hibernates on a

fir-tree—_Picea excelsa_—and in the spring lays numerous eggs; these hatch,

and by the effects of suction of the _Chermes_ on the young shoots, galls

are formed (Fig. 286), in which the Insects are found in large numbers;

when they have grown the galls open, and allowing the Insects to escape

these moult and become winged females. They now take on different habits;

some of them remain on the _Picea_, lay their eggs thereon, and out of

these there are produced young that grow into hibernating females, which

next spring produce galls as their grandmothers did; but another portion

migrates to the Larch (_Larix_); here eggs are laid, from which proceed

wingless parthenogenetic females, that hibernate on their new or secondary

plant, and in the following spring lay their eggs and give rise to a

dimorphic generation, part of them becoming nymphs and going on to the

winged condition, while the other part remain wingless and lay eggs, that

give rise to yet another wingless generation; in fact, a second pair of

parallel series is formed on the new plant, of which one is wingless, and

exclusively parthenogenetic, and continues to live in this fashion for an

indefinite period on the secondary plant, while the other part becomes

winged; these latter are called sexuparous, and go back to the _Picea_, and

there lay eggs, that give rise to the sexual forms. If we would summarise

these facts with a view to remembering them, we may say that a migration of

a part of a generation from the _Picea_ was made with a view of producing a

sexual generation, but that only a portion of the migrants succeeded in

effecting the object of the migration, and this only in their third

generation. Thus portions remained on the _Picea_, {587}producing unisexual

(female) individuals, and a portion of those that emigrated to the _Larix_

remained thereon, producing also unisexual (female) individuals, while the

others returned to the _Picea_ and produced a sexual generation. How long

the production of the unisexual generations may continue has not been

determined.

_Phylloxera._—The _Phylloxera_, that has caused such an enormous amount of

damage in the Old World during the last thirty years, is a small Aphid that

was introduced from North America into Europe. In North America it is not

so injurious as it is in Europe, owing, no doubt, to slight distinctions in

the conditions of life in the two hemispheres, as one of which may be

mentioned that in Europe a larger proportion of the individuals produced

appear to confine themselves to feeding on the roots, _P. vastatrix_ being

one of the species that lives both in galls on leaves, and underground on

the roots. The species is one that exhibits in their most complex form the

peculiar phenomena of Aphid life we have already mentioned. It has probably

only one congener, _Phylloxera quercus_, and of this Lichtenstein says that

in its cycle, from the starting-point of the winter-egg to the assumption

of the sexual condition, it exhibits a series of no less than twenty-one

forms.[526] The life of _Phylloxera vastatrix_ apparently differs

essentially from what we have described in _Chermes_, inasmuch as the

migrations are only between leaf and root of the same plant—the vine—and

not from one species of plant to another. Some authorities treat

_Phylloxera_ and _Chermes_ as a separate family under the name of

Phylloxeridae.

[Illustration: Fig. 286—Gall, or false cone of _Chermes abietis_.

Cambridge. The small figure, to the left, is a section made at the level

indicated by the pointing line _a_, and shows the chambers containing

young.]

_Galls._—Like _Phylloxera_, many species of Aphidae live partially, others

wholly, in galls that are produced by plants as the result of one or more

Aphids interfering with a delicate part of the plant when it is in a young

and growing state. The usual position of Aphid galls is on a leaf or

leaf-stalk. But in the case of the genus _Chermes_, {588}a bud or some

growing part of the spruce-fir is affected in such a way that it gives rise

to an object having externally the appearance of a little fir-cone, while

inside it consists of chambers in which the Aphids reside. The forms of

Aphid-galls are very diverse, but this is probably due to the plant rather

than to the Insect, for the same species of Aphis may give rise to

different forms of galls. Réaumur thought that each Aphid-gall was due to a

single individual that irritated the tissue of the plant, so that the

latter grew up at the point of irritation and enclosed the Insect.

A few points as to the anatomy of Aphids should be noticed. It is doubtful

whether the antennae have ever really more than six joints, the apparent

seventh joint being actually a sort of appendage of the sixth. The rostrum

is externally three-jointed, and is remarkable for the great diversity in

its length, sometimes it is quite short, at others several times longer

than the body (Fig. 285); the setae are often very much longer than the

sheath; in cases where this great length of rostrum exists, the individual

may often be found with the tip firmly fixed in the bark, and, as it were,

tethered by means of the rostrum, the length of which allows, nevertheless,

considerable locomotion. Suction is performed by contractions of the

pharynx. There has been much difference of opinion as to whether there is a

salivary syringe, and Witlaczil failed to find it. Krassilstschik is,

however, positive that it exists,[527] and that it is analogous to that

described by Mayer in _Pyrrhocoris_, but there are great differences of

structure between the two. It is very difficult to determine the number of

segments at the extremity of the body; this is terminated dorsally by a

median organ placed above the anus, and known as the cauda. Balbiani

apparently considers that there are ten abdominal segments and the cauda.

The alimentary canal has a small stomach, and an elongate intestine, the

terminal division of which is capacious and remarkably long. There are no

Malpighian tubes; according to Kowalevsky, their function is discharged by

the posterior part of the alimentary canal. There exists, however, a

peculiar structure, the pseudovitellus, a sort of cellular, double string;

and Witlaczil, in his valuable paper[528] on the anatomy of Aphidae,

suggests that this {589}organ may in some way replace the missing

Malpighian tubes. Another highly peculiar structure is the siphons,

frequently called nectaries, honey-tubes, or siphuncles. They are situated

on the dorsal aspect of the fifth abdominal segment, but exist only in

certain of the sub-families; they are of very different lengths according

to the species, and are capable of movement; they open directly into the

body cavity, though exceptional openings into the body cavity are extremely

rare in Insects. They excrete a waxy matter, which first appears as

oil-like globules. It was formerly supposed that they were the means of

secreting the sugary matter, called honey-dew, so much prized by ants and

some other Insects; but this is now ascertained to be erroneous. This

matter comes from the alimentary canal, and is secreted in large quantities

by some species, Büsgen having observed that forty-eight drops, each about

1 mm. in diameter, were emitted by a single individual in twenty-four

hours.[529] Certain gall-dwelling Aphidae—_Pemphigus_, _Chermes_ (Fig.

285), _Schizoneura_—possess numerous wax glands; these seem to replace the

siphons, and excrete the peculiar, whitish flocculent matter that is so

conspicuous in some of these Aphids.

Earlier anatomists failed to find any dorsal vessel, and it is consequently

reported in books to be absent. It has been, however, recently detected by

Witlaczil, and Mordwilko states that it does not differ from that of other

Insects.

We have already alluded to the fact that the mode of reproduction of Aphids

leads to an unrivalled increase. This, however, is not due to the

prolificness of the individual, which, in point of fact, appears to be

considerably below the average in Insects, but rather to the rapidity with

which the young begin to reproduce. This has been discussed by Huxley,

Buckton, and others. The first-named naturalist calculated that the produce

of a single _Aphis_ would, in the course of ten generations, supposing all

the individuals to survive, "contain more ponderable substance than five

hundred millions of stout men; that is, more than the whole population of

China."[530] It has since been contended that Professor Huxley's

calculation was much below the mark. Although it is somewhat difficult to

make a calculation dealing adequately with the actual facts, yet it is

clear that the increase {590}of Aphids is such that, drawing as they do

their nutriment directly from the plant in its growing state, in the course

of two or three years there would be no nutriment available for other

animals, except such as might be derived from plants not attacked by

Aphids. The numbers of Aphidae would be so great that they could not be

expressed by ordinary numerical methods, and their increase would be

actually limited only by the relations existing between different kinds of

plants, and between plants and Aphids. This result is avoided by the fact

that Aphids are themselves the victims of a whole army of Insect enemies.

They have the numerous members of a special group (Braconidae, Aphidiides)

of minute Hymenoptera to live inside their bodies, and many Aculeate

Hymenoptera depend entirely on the Aphidae as the source of food for their

own progeny. The Lady-birds—Coccinellidae—live on Aphids and Coccids, and

themselves increase to such an extent as to be in many years a conspicuous

part of the Insect world. Crowds of the larvae of Hemerobiids and Syrphids

are constantly engaged in spearing and sucking the Aphides. Hence the old

naturalist Bonnet said that, just as we sow grain for our benefit, Nature

has sown Aphids for the benefit of multitudes of different Insects. He

might have added that these different Insects are for the benefit of man,

it being clear that without them the population of the world must rapidly

decrease.

Ants treat Aphidae more intelligently than most other Insects do, for they

do not destroy the helpless creatures, but utilise their products in the

way man does those of the cows he keeps. The relations between ants and

Aphids is itself an extensive chapter in Natural History; many facts have

been brought to light showing that the ants manage the Aphids in a prudent

or intelligent manner, distributing them when too numerous in one place,

keeping guard over them, even building shelters for them, and in some cases

keeping them in direct association, by retaining the Aphids in their own

dwellings. The further investigation of these points goes, the more it

tends to raise the actions of the ants to the level we call in ourselves

intelligent. It would even appear that the ants are acquainted with the

migrations of the Aphids from one species of plant to another, Webster

informing us that as the Aphis-population on an apple tree multiplied the

ants in attendance anticipated their migration to wheat and grass {591}by

carrying them to those plants.[531] We have nearly 200 species of Aphidae

in Britain,[532] and there may perhaps be 800 known altogether. To what

extent they may occur in the tropics is undetermined. There are said to be

no native species in New Zealand.

[Illustration: Fig. 287—Instars of _Aleurodes immaculate_. Europe. (After

Heeger.) A, Nymph, from above; B, nymph, under surface; C, imago.]

FAM. 8. ALEURODIDAE.—_Minute Insects, with four mealy wings, seven-jointed

antennae, two-jointed feet, terminated by two claws and a third process._

These minute Insects are at present a source of considerable perplexity,

owing to the curious nature of their metamorphosis, and the contradictory

accounts given of them. In the earlier stages they are scale-like and

quiescent, being fixed to the under side of a leaf. The French authors

Signoret and Girard state that the young are hatched having visible

appendages and segmentation, but that after they are attached to the leaf

the organs gradually suffer atrophy. Maskell states the opposite, saying

that the organs in the earliest stages are not usually recognisable, but

become faintly visible with the growth of the Insect. Heeger states that

the larva undergoes three ecdyses, and he gives the figures we reproduce;

if he be correct it would appear that the nymph undergoes a great

development. Réaumur, on account apparently of their great metamorphosis,

treated the species {592}known to him as being Lepidopterous, though he

correctly pointed out their distinctions. At present we can only conclude

that the Aleurodidae undergo a metamorphosis of a kind peculiar to

themselves, and requiring renewed investigation. The family has been

monographed by Signoret, and more recently by Maskell, who has increased

the number of species to about sixty.[533] We have three or four in

Britain, one of which, _A. brassicae_, is extremely abundant on various

kinds of cabbage in certain years.

[Illustration: Fig. 288—Scale-Insect. A, _Aspidiotus camelliae_, on the

stem of a plant; B, a female scale magnified. (After Green.)]

FAM. 9. COCCIDAE (_Scale-Insects_, _Mealy-bugs_).—_Insects, usually minute,

with only a single claw to the foot; the male with one pair of wings, but

without mouth-parts; the female wingless and usually so degraded in form

that most of the external organs and appendages cannot be distinguished._

The form in which these Insects are most generally known is that of a small

scale or shell-like body closely adhering to leaves, fruits, or bark. The

scales are of the most varied form, so that no general description can be

given of them. The scale may be defined as an accumulation of excreted

matter, combined with the cast skin or skins of the Insect, covering the

body either totally or partially, and thus acting as a shield under which

the subsequent development takes place. All Coccidae do not form scales;

but the habit of excreting a large quantity of peculiar matters to the

outside of the body is universal; this excreted substance is frequently

white, and of a powdery nature, and Coccids of this kind are known as

mealy-bugs. In other cases the exudation is like shell or glass, and the

creature may become quite encysted therein. In this way the forms of

Cocidae known as "ground-pearls" are formed. When first hatched from the

egg Coccidae are mite-like creatures, and it is only subsequently that the

females lose the power of locomotion. The females of numerous forms of

Coccidae—more particularly the mealy-bugs—do not lose the antennae and

legs. There is also a group (Brachyscelides) of Coccids that live in

{593}galls. This highly aberrant group is, however, peculiar to Australia;

elsewhere very few gall-making Coccids have been discovered.

[Illustration: Fig. 289—_Dactylopius longispinus._ Female on portion of a

fig-leaf. (After Berlese.)]

There are upwards of 800 species of Coccidae at present known.[534] The

family was monographed by Signoret about twenty-five years ago, and since

then there has been very much matter concerning them published in a

scattered manner.[535] No general work has been published on the British

species, but Mr. Newstead is preparing one. The classification of Insects

so minute as Coccidae, and with such extreme difference in the sexes, is,

of course, a matter of great difficulty; the best divisions are those given

by Green in his _Coccidae of Ceylon_.[536]

The fact that there is only one pair of wings in the perfect male Coccid

would appear to ally these Insects with the Diptera; these Coccidae have,

too, like the Diptera, a small appendage on each side of the metathorax.

Witlaczil shows that these little processes may really represent a pair of

wings, inasmuch as they are developed from imperfect folds of hypodermis,

_i.e._ imaginal discs. Beyond these facts and the occurrence in certain

females (Margarodes) of a great histolysis during the post-embryonic

development, there is nothing to indicate any relationship between Coccidae

and Diptera. It has been shown by Riley that these little processes, in

some forms, serve as hooks to attach or control the true wings, and this

function is never assumed by the halteres of Diptera. Although Coccidae are

placed next Aphidae, yet the two families appear to be really very

different. The modes of reproduction so peculiar in Aphidae reappear to a

certain extent in Coccidae, but are associated with profound

{594}distinctions. Though the viviparous method of reproduction and

parthenogenesis occur in Coccidae, yet they are only exceptional, and they

are not put to the same uses by the species that exhibit the phenomena.

Thus we have seen that in Aphidae generations of imperfect individuals are

produced with rapidity, while the individual is not directly very prolific.

In Coccidae the reverse is the case—the generations are usually similar to

one another; they do not, as a rule, follow with rapidity, and the female

is usually very prolific, thousands of young being sometimes produced by a

single individual. The extraordinary polymorphism of the species of Aphidae

is not exhibited by Coccidae, though, contrary to what we find in Aphidae,

the males and females are usually excessively different. The two families

apparently also differ in that Coccidae are specially characteristic of

warm climates, Aphidae of the temperate regions.

PARTHENOGENESIS.—Owing to the fact that the males are very minute

creatures, totally different from the females, and living but a very short

time, they were but little known to the earlier observers. It was therefore

only natural to suppose that parthenogenesis was very common. Of late years

the males of a great many species have become known, so that ordinary

sexual reproduction must be considered as the normal method in Coccidae,

although, in the great majority of cases, the male is still unknown. It

has, however, been shown in numerous cases that parthenogenesis may occur

even when males exist; and there are some abundant species of which it has

not been possible to find a male. In 1887 Moniez[537] announced that he had

discovered the male of _Lecanium hesperidum_ (one of the notoriously

parthenogenetic species) in an ovarian cul-de-sac in the body of the

female, and he therefore considers that sexual reproduction occurs. He does

not say how pairing takes place, and we are not aware that his observation

has been confirmed. If correct it will be necessary to reconsider the whole

question as to parthenogenesis in Coccidae. Apterous males are known in two

or three species.

The post-embryonic development of Coccidae is of the most unusual

character. It is quite different in the two sexes, and in each of them it

presents features not found elsewhere. It has, however, as yet been studied

in only a few forms, and even in them is incompletely known.

{595}[Illustration: Fig. 290—Instars of _Dactylopius citri_. (After

Berlese.) A, Egg; B, young larva; C, first male nymph; D, second male

nymph; E, adult male; F, adult female. All equally magnified. x 20.]

When hatched from the egg the young Coccids are all similar, male and

female being indistinguishable. A difference soon appears, with the result

that the male, after passing through more than one pupal condition, appears

as a winged Insect. The female never becomes winged, but, if we may judge

from the incomplete accounts we at present possess, her development varies

much according to species. In some she retains the legs, antennae, and

mouth-organs; in others she loses these parts, though retaining the

original form in a general manner; while in a third (_Margarodes_) she

becomes encysted, and apparently suffers an almost complete histolysis,

reappearing after a very long period (it is said it may be as much as seven

years) in a considerably altered form. The post-embryonic development of

_Aspidiotus nerii_ has been studied by Schmidt[538] and Witlaczil,[539]

whose accounts agree except as to some points, such as the number of

ecdyses. The young, or larva, is hatched with fairly well-developed legs,

antennae, and rostrum; there is no external difference between the sexes.

The larva selects some spot on the plant and drives its rostrum therein,

thus becoming fixed; moults occur, and the body excretes waxy matter from

its sides in processes that fell together and form the shield; the female

becomes much larger than the male. The legs and antennae of both sexes

disappear, so that the power of movement is completely lost. The

mouth-parts also atrophy. The female after this undergoes no further

change, except that of growth in connection with ovarian development.

{596}[Illustration: Fig. 291—Development of male of _Aspidiotus nerii_. A,

Newly hatched larva; B, prae-pupal instar; C, pupa before ecdysis; D, pupa

shortly before the emergence of the imago: _a_, antenna; _e_, eye; _f_,

wing-rudiment; _l_, leg; _o_, basal part of mouth-organs. (After Schmidt.)

Magnification not definitely stated.]

The male, however, continues development; notwithstanding the impossibility

of taking food, owing to the absence of a mouth, it increases much in size,

and the organs of the future perfect Insect commence to develop from

imaginal discs in a manner similar to that which occurs in the Dipterous

genus _Corethra_; no mouth-parts are however developed, these being merely

represented by spots of pigment, or rudimentary additional eyes. The wings

are developed outside the body. Difference of opinion prevails as to the

nature of the instars between the young larva and the imago. It is clear,

however, that Fig. 291, D, corresponds fairly with the pupa of Insects with

complete metamorphosis, and the instars shown in Fig. 291, B, C, may

therefore be looked on as equivalents of the resting-larva stage of

ordinary Insects with complete metamorphosis. Witlaczil considers this

development to be a condition of incomplete, approaching very nearly to

complete, metamorphosis. The condition is perhaps more precisely estimated

if we recollect that winged Insects are divided into two series, in one of

which the wings are developed outside the body; in the other, inside the

body. The Insects with very complete metamorphosis all belong to the second

of these two series, while in the male Coccid we have the highest form of

metamorphosis attained by any of the first series. As regards the

development of the female encysted nymph or pupa, previously alluded to as

being found in the "ground-pearls" of {597}the genus _Margarodes_, we can

at present offer the reader no satisfactory account.[540]

PRODUCTS OF COCCIDAE.—Honey-dew is secreted by Coccidae, but as a rule not

so extensively as by Aphidae and some other Homoptera; nevertheless, it is

often sufficient to make the plants frequented by Coccids very sticky and

unclean. Some species make a really extensive exudation of such matter.

Réaumur records that a Coccid, which is doubtless _Lecanium persicae_,

excretes a supply of honey-dew that drips to the ground; he says it tastes

sweet and nice. The manna mentioned in the book of Exodus is pretty

certainly the honey-dew secreted by _Coccus_ (now _Gossyparia_)

_mannifera_, which lives on _Tamarix_ in many places in the Mediterranean

basin. This substance is still called by the Arabs "Man," and is used as

food; in its natural state it is a substance very like honey; it is

doubtless excreted by the _Coccus_, and is not produced directly by the

_Tamarix_ as some have supposed. Waxy matters are produced by several

Coccidae. _Ceroplastes ceriferus_, a Lecaniid, produces white wax in India.

_Ceroplastes_ is a widely distributed genus, and various species of it have

been used for the purpose of producing wax in other parts of the world. The

white wax of China is understood to be produced by another Lecaniid,

_Ericerus pela_; but little is known as to this Insect; it is said that the

wax is produced by the winged males. The substance was formerly greatly

prized in China, but is falling into disuse on account of the introduction

of Kerosene. Lac is produced by _Carteria lacca_, a Lecaniid living in

India on _Anona squamosa_, as well as on species of _Ficus_, _Rhamnus_ and

other trees; the lac is the shelly scale produced by the Insect as a

covering; it is composed in larger part of resinous matter, with which

there is mixed a comparatively small quantity of wax and other substances.

The body of this Insect also affords the red substance called lake. Various

species of _Kermes_ formerly afforded a red dye well known to the Greeks

and Romans. These Insects live on _Quercus coccifera_ in the Mediterranean

region. A medicinal syrup is also obtained from them. _Porphyrophora

polonica_ was used in North and Central Europe for the same purposes as

_Kermes_; it is a Coccid living on the roots of _Polygonum cocciferum_.

These European Insects were replaced commercially {598}after the discovery

of America by the cochineal Insect, _Coccus cacti_, a Mexican Coccid

feeding on a Cactus called Nopal (_Opuntia coccinellifera_). This Insect

was subsequently introduced to the Eastern hemisphere, and was established

with more or less success in a few spots on the borders of the

Mediterranean. In the Canary Islands it flourished on other species of

_Cactus_, became acclimatised, and was the object of an extensive commerce.

The colour in the case of all these Coccid dyes was obtained from the

bodies of the Insects, in the tissues of which it is contained. The dyes

have now been largely displaced in commerce by the derivatives of Aniline.

Axin is produced by the Mexican Coccid _Llaveia axinus_; this substance

appears to be of a very peculiar nature; it is apparently chiefly fatty,

and contains a peculiar acid, axinic acid. Axin is used as an external

medicinal application in various affections; and it is also employed as a

varnish; it dries and hardens on exposure to the air, and is said to be of

considerable value.[541] In our British genus _Orthezia_ the body of the

female is completely covered with a symmetrical snow-white armour, from

which project the pink legs and antennae. This is one of the forms in which

the female preserves the legs to the end of her life. The objects called

ground-pearls, already alluded to, have long been known in various parts of

the world, and in the island of St. Vincent they are sufficiently large to

be collected and strung for necklaces. These bodies are the encysted pupae

of Coccids of the genus _Margarodes_; the cyst is said to be of chitin. _M.

vitis_ commits serious ravages on the vines in Chili by sucking their

roots, and it is probable that all the species are of subterranean habits;

this would partially explain the fact that very little is known about the

history of these pearls, though naturalists have been acquainted with them

for many years.

The gall-making Coccids of the group Brachyscelides have only recently been

at all investigated; the galls they give rise to are sometimes about a foot

in length, and there appear to be numerous species and several genera in

Australia; they are especially abundant on _Eucalyptus_ and Acacias. The

females are highly remarkable from the variable conditions the legs assume,

so that in some cases they may be described as biped Insects, the {599}hind

legs remaining, though the others have atrophied.[542] Very little indeed

is known as to these Insects. One of the most peculiar points of their

economy appears to be that the galls giving rise to males are different

from those producing females.

ANOPLURA or LICE.

[Illustration: Fig. 292.—_Pediculus capitis_, ♀. Human head. (After

Piaget.)]

_Small Insects with thin integument; entirely wingless, the three thoracic

segments indistinctly separated; the head bearing in front a short tube

furnished with hooks; from which tube there can be protruded another very

delicate sucking-tube. Feet terminated by a single long claw._ The

Anoplura, Pediculidae, or lice are disgusting Insects about which but

little is known. The most contrary opinions have been expressed as to their

mode of taking their nourishment, which is, without exception, the blood of

Mammals; on the bodies of which they pass the whole of their life. It is a

most difficult matter to examine their mouth; the best information on this

point is given by Schiödte and Graber, but though these two authorities

agree, their results are very incomplete, and do not warrant us in

expressing a confident opinion as to the nature of the relationship between

Hemiptera and Anoplura—a question that has been for long a moot one. The

short tube furnished with hooks in front (Fig. 293, _d_) is considered to

be the lower lip, and the tube inside is, it is suggested, a combination of

the homologues of maxillae and mandibles; there is also what may be a

labrum (_g_); and inside the head a framework, at any rate analogous to if

not homologous with, the parts of this kind we have described as existing

in Hemiptera. All the parts, with the exception of the basal tube or head

of the beak, are of the most minute and delicate nature, so that it is

difficult to see their form or comprehend their relations. It is evident

that they are very different anatomically from the mouth-parts of

Hemiptera; still there is {600}sufficient general resemblance to warrant

the belief that the parts in the two may ultimately be shown to be also

morphologically similar. If Meinert be correct, this view will, however,

not prove to have any foundation. He considers that morphologically the

mouth of the louse has no similarity to that of the bug; the protrusible

parts in the former he considers to be modifications of epipharynx and

hypopharynx; and the rod-like structures to be hypopharyngeal lamellae; and

that they are thus totally different from the setae of bugs.[543] He

considers Lice to be a distinct Order of Insects for which he proposes the

name Siphunculata.

The alimentary canal and nervous system resemble those of Mallophaga more

than they do those of Hemiptera. The oesophagus leads into a large stomach

bilobed in front; at the posterior extremity of this there open the four

Malpighian tubes, and behind these there is a well-marked small intestine.

The nervous system consists of a cephalic ganglion and of three other

closely approximated ganglia, the posterior one the larger. It remains

doubtful whether or not the first of these three ganglia is the

infra-oesophageal one.[544]

[Illustration: Fig. 293.—Mouth-organs of louse. (After Graber.) _b_, _c_,

Chitinous envelope into which the beak can be withdrawn; _d_, head of the

beak, with crown of spines; _g_, labrum; _h_, delicate tube protruded (very

rarely seen in this state); _m′_, unpaired muscle.]

The species of lice, so far as known, are not numerous, some six genera and

about forty species being all that are recorded; they occur on various

kinds of mammals, including some that live in water. Seals have a genus,

_Echinophthirius_, peculiar to them. Monkeys are specially liable to be

affected by lice; the genus that chiefly occurs on them is _Pedicinus_, a

very distinct one, in which there are only three instead of five joints to

the antennae. Perhaps the most remarkable louse is _Haematomyzus

elephantis_, that of the elephant; it has a long proboscis in front of the

head. As a rule each species of louse is confined to one species of

Mammalia, or to very closely allied forms. Man is said to be infested

{601}by three species, _Pediculus capitis_, _P. vestimenti_ and _Phthirius

inguinalis_; Meinert is of opinion that _P. capitis_ and _P. vestimenti_

are only one species, and Schiödte appears also to have thought this

probable. Andrew Murray was of opinion that the heads of different

varieties of men are infested by distinct varieties of _P. capitis_. His

conclusion was chiefly based on examination of specimens preserved by

Charles Darwin; it requires confirmation. Very little is known as to the

life-history of the louse. Leeuwenhoek made himself the _corpus vile_ for

an experiment, from which he concluded that the _Pediculus vestimenti_ is

very prolific. That scientific men did not know whether the louse bites or

sucks was formerly made the ground for a taunt. Schiödte has given an

almost pleasing account of the way in which he settled this,[545] showing

that the sucking action is beyond all doubt. Accounts of disease called

Phthiriasis, attributed to lice, are to be found in many old books, but the

evidence does not warrant us in believing anything more than that persons

suffering from some disease, and in a neglected and filthy condition, were

horribly infested with these disgusting Insects.

It is usual to say that Pediculidae are Hemiptera degraded by a long

exclusive persistence in parasitic habits. At present, however, this must

be looked on as a pious opinion, rather than as an induction from our

knowledge of their morphology and embryology; for this is at present too

imperfect to warrant any final conclusion.

{602}NOTES AND CORRIGENDA

VOL. VI.

Note to P. 4: _Classification of Hymenoptera._ Mr. W. Ashmead has

published[546] a sketch of a new classification of Hymenoptera, in which

the points we have suggested are given effect to; the first division of the

Petiolata being carried out with reference to the position of the

ovipositor, while part of the Proctotrypidae is brought into the Aculeate

division. We cannot, however, commend this arrangement as final, for

several points have not received sufficient consideration.

Note to P. 172, line 22. For the words "We shall subsequently see,"

substitute "We have previously said" (p. 161).

Note to P. 350, line 10 from bottom: _instead of_ "only one genus," _read_

"only one Old World genus."

Note to P. 541, line 16: _instead of_ "two" _read_ "ten."

VOL. V.

P. 217, line 4. _For_ sterna _read_ nota.

P. 271. The lettering of Fig. 158 is erroneous; under the lower pointing

line the letter d should be inserted, and the left hand upper pointing line

should bear the letter c _instead of_ d.

P. 277, line 7. _Instead of_ Fig. 162, _read_ Fig. 163; and line 9,

_instead of_ Fig. 163 _read_ Fig. 164.

P. 378. The species figured has since been described by Mr. Haviland as

_Termes malayanus_.

P. 380. The species figured has since been described by Mr. Haviland as

_Termes mirabilis_.

P. 383. _Hodotermes japonicus._ It has been recorded (_P. Boston Soc._ xii.

1869, p. 139) that this is not a Termite, but an immature form of the

earwig _Brachylabis maritima_.

Pp. 480 and 481. It is not made clear that the distinction in the number of

joints of the palpi of Phryganeides and Limnophilides applies to the males

only; in both groups the number of joints in the females is five. The

remark as to Phryganeides occurring in the Southern Hemisphere is

erroneous. It is Limnophilides that reappear in Chili, not Phryganeides.

P. 490. Fig. 333 A, _f_ and its line point to a division of the mesonotum,

not of the metanotum.

P. 564. Habits of _Pelecinus_. Mr. S. A Forbes has recorded an observation

suggesting that _P. polyturator_ may be a parasite of Lamellicorn beetles

of the genus _Lachnosterna_. See _Rep. Ins. Illinois_, xix. 1896, p. 79.

{603}INDEX

Every reference is to the page: words in italics are names of genera or

species; figures in italics indicate that the reference relates to

systematic position; figures in thick type refer to an illustration; f. =

and in following page or pages; n. = note.

Abdomen, of _Chrysis_, 2;

of Coleoptera, 185;

of Diptera, 446;

of Hemiptera, 538;

of Lepidoptera, 313;

of Thysanoptera, 528

Abdominal legs, 9

Abeille-perce-bois, 33

Abeille tapissière, 51

_Abispa_, 77

_Acacia fistulosa_, beetles in, 213

Acalyptrate Muscidae, _494_

_Acanthia_, _560_

Acanthomeridae, 483

_Acanthosoma griseum_, 546

Acari, relations to Insects, 220, 223, 238, 530

_Acentropus_, 425

Acephalous larvae, 449

Achreioptera, _219_

Acraeides, 350

_Acridium maroccanum_, 254

_Acrocera globulus_, 490

Acroceridae, 489

_Acronycta_, 418

_Actias luna_, 374

Actiidae, _510_

Acutilingues, _20_

Adapted excrement, 284, 284, 380

_Adelops_, 221

Adensamer, on _Ascodipteron_, 520

Adephaga, _190_, 200 f., _216_, _234_

Adimeridae, 240

_Adimerus setosus_, 241

Adlerz, on _Formicoxenus_, 160;

on _Tomognathus_, 161

Adminicula, 327

_Aëdes_, 455 n.

_Aegeria_, 387

Aegeriidae, 386

Aegialitidae, 265

_Aegocera tripartita_, 411

_Aenictus_, 159, _179_, _180_

_Aenigmatias blattoides_, 495

_Aeolothrips fasciata_, 528

Aëpophilidae, 559

_Aëpus_, 206

Aërostatic setae, 408

Aërostats, 449

Aganaidae, 408

Agaristidae, _370_, _371_, 410

_Agdistes_, 426

Agdistinae, _426_

_Agenia carbonaria_, _A. hyalipennis_, 105

_Ageronia_, 354

_Aglycyderes setifer_, 298

Aglycyderidae, 297

Agromyzidae, _504_

_Agrotis_, 415;

_A. spina_, 417

Ahuatle, 504

_Alaena_, _350_

_Alaopone_, 179, 180

Alar organs—see Wings, Elytra, Tegmina

_Aletia xylinae_, 416

_Aleurodes brassicae_, 592;

_A. immaculata_, 591

Aleurodidae, 591

_Alucita_, _426_;

_A. polydactyla_, 426

Alucitidae, 371, 426.

Alula, 447

_Amara_, 205

Amber, Insects in, 144, 269, 458

_Amblyopone_, 180

Amblyoponides, 132, 180

Ambrosia, 295

_Ambryllis_, 409

_Amicta quadrangularis_, 394

_Ammophila_, 111;

_A. affinis_, 111;

_A. hirsuta_, 111;

_A. holosericea_, 111

Amphicyrtides, _242_

_Amphidasis betularia_, 412, 414

Amphiodont, 193

Amphipneustic, 450

_Amphizoa lecontei_, 207

Amphizoidae, 207 {604}

_Ampulex compressa_, 114, 115;

_A. ruficornis_, 115;

_A. sibirica_, 114

Ampulicides, 114 f., 169

Amycterides, 291

Anal armature, 328, 416

Anal nervures, 318

_Anaphe_, 376

Anaspini, 267

_Anaspis_, 268

Anatomy—see External Structure and Internal Anatomy

Anchor-process, 459

Ancient, Lepidopteron, 435—see also Primitive

Ancylolominae, _425_

_Andrena_, _23_, 25, 30, 301, 303;

hair of, 11;

_A. labialis_, 488;

_A. nigroaenea_, 23;

_A. ovina_, 30

Andrenidae, _20_

Andrenides, 23

_Andrenimorpha_, 388

Andrenoides, _20_

Androconia, 331 f.

_Anergates atratulus_, 160 f.

Angelitos, 63

_Anisopteryx aescularia_, 411

_Anisotoma cinnamomea_, 222

Anisotomidae, _223_

Anisotomides, 222

Anlagen, 143

Anobiides, 247

_Anobium_, 254;

_A. paniceum_, 247;

_A. striatum_, 248;

_A. tessellatum_, 248

_Anochetus ghiliani_, 174

_Anomma_, 178

_Anophthalmus_, 205

Anoplura, 599 f.

_Anosia erippus_, _A. menippe_, 345;

_A. plexippus_, 307;

larva, 324;

pupa, 327

Antennae;

of _Belostoma_, 566;

of flies, 441;

of Lamellicornia, 191;

of Lepidoptera, 307;

of butterflies, 340, 341;

of Sphingidae, 380

_Antherophagus_, 235

Anthicidae, 266

_Anthidium_, 45;

_A. bellicosum_, 47;

_A. diadema_, 45;

_A. manicatum_, 45;

_A. septemdentatum_, 47;

_A. strigatum_, 30

_Anthocopa_, 51

Anthocoridae, _560_

_Anthomyia angustifrons_, _A. brassicae_, _A. cana_, 506

Anthomyiidae, 506

Anthophila, 10 f.

_Anthophora_, 32, 33;

destroyer of, 272, 274;

_A. personata_, 33;

_A. pilipes_, 33;

proboscis of, 17

_Anthothrips aculeata_, 530

Anthracides, 486

_Anthrax_, 486 f.;

_A. fenestralis_, 489;

_A. trifasciata_, 44

_Anthrenus fasciatus_, 241

Anthribidae, 278, 290

Antisquama, 448

Antitegula, 447

Ant-plant, 138, 139, 168

Ants, 131 f.;

and Aphidae, 590;

and caterpillars, 356

Ants'-nest, Insects, 200, 213, 221, 223, 224, 225, 231, 236, 240, 548;

larva, 501, 502

Anus, 314, 320

Aorta, 320

Aortal chamber, 320

_Apate capucina_, 246

_Apatela_, 418

_Apathus_ = _Psithyrus_, q.v.

Apatidae, 246

_Apatura_;

larvae, 354;

_A. iris_, 344

Apaturides, 352

_Aphaenogaster_, 164, 165, 221;

_A. arenarius_, 164;

_A. barbarus_, 131, 164;

_A. structor_ 164, 240

Aphaniptera, 522 f.

_Aphanocephalus_, 228

_Aphelocheirus_, 565

Aphidae, 581 f.;

and ants, 181

Aphidiides, 590

_Aphis maidi-radicis_, 584

_Aphomia sociella_, 424

Apidae, 10 f., 20, _32_

Apioceridae, 492

_Apis_, _53_;

_A. adansonii_, 69;

_A. domestica_, 68;

_A. dorsata_, 69;

_A. fasciata_, _A. ligustica_, 68;

_A. mellifica_, 65 f.;

feet of queens and workers, 69;

ligula of, 16;

worker and hairs, 12

_Apoda_, 402;

_A. testudo_, etc., 401, 402

Apodidae, 402

_Apoica pallida_, nest, 83

_Aporia crataegi_, 322

Appetite, 491

_Apterogyna_, 96

_Apterona_, 393, 394;

_A. crenulella_, var. _helix_, 395

Apterous, beetles, 187, 263;

females, 95, 96, 140, 171, 174, 315, 392, 393, 407, 413, 430, 592—see

also Workers;

Insects, 95, 96, 474, 495, 496, 505, 518, 531, 581;

males, 140, 160, 161, 172, 585, 594

Aquatic;

caterpillar, 377;

cocoons, 280;

larva, 421 f., 425, 504;

pupa, 423

Aradidae, 550

_Aradus orientalis_, 550

_Araeocerus_, 290

_Araschnia levana_, _A. prorsa_, 353

Arbelidae, _369_, 396

_Arceina_, 373

Archiapidae, _21_, _22_

Archiapides, _21_ f.

_Arctia caja_, 308;

_A. villica_, 410

Arctiidae, _370_, _404_, 408, _410

Argiva_, 414 {605}

_Argynnis_, larvae, 354;

_A. paphia_, androconia, 332

_Argyromoeba sinuata_, 76;

_A. trifasciata_, 486

Arista, 442

Army-worm, 416

_Aromia moschata_, 188

_Arthropterus_, 214

_Asclera caerulea_, 267

_Ascodipteron_, 520

_Asemorhoptrum lippulum_, _160_

Asilidae, 491

_Asilus_, 492;

_A. crabroniformis_, 441

Asparagus-beetle, 281

_Aspidiotus camelliae_, 592;

_A. nerii_, 595, development of, 596

_Aspidiphorus_, 246

_Aspidomorpha_, pupa, 283, 284

Association, of _Anergates_ and _Tetramorium_, 160;

of ants and other Insects etc., 180 f.;

of _Formica_ and _Formicoxenus_, 159;

of _Strongylognathus_ and _Tetramorium_, 162;

of _Tomognathus_ and _Leptothorax_, 161

_Astata boops_, 119

_Astatides_, 119

Asteidae, _504_

_Astomella lindeni_, 490

_Astynomus_, 285

_Atemeles_, 225;

and ant, 182

Athericerous, 441

_Atherix_, 481;

_A. ibis_, 480

_Athous rhombeus_, 257

_Atractocerus_, 254

Atrophy of mouth and stomach, 310

_Atta_, 137, 164 n., 165, 502

_Attacus_, 373;

_A. atlas_, 373

Attelabides, 291

Attini, 158, 159, 165

Attitude, 381, 384, 385, 388, 412, 413, 425, 429

_Atylotus fulvus_, 483

_Autocrates aenea_, 275

_Automeris_, 373

Axin, 598

_Azteca_, 158

Azygos oviduct, 321

_Badamia exclamationis_, 365

Barrett, on increase of melanism, 414

Basket-worms, 393

Bat-parasites, 521, 560

Bataillon, on metamorphosis, 306

Bates, H. W., on classification of butterflies, 344;

on homoeochromatism, 351;

on _Megacephala_, 201

Batesian mimicry, 337, 339

_Bathyscia_, 221

Beak, 532

Beauregard, on vesicating Insects, 275

Beaver, Insect on, 219, 221

Becher, on mouth of Diptera, 444 n.

Bed-bug, 559;

enemy of, 558

Beddard, on animal coloration, 339 n.

Bee (_i.e._ honey-bee)—see _Apis mellifica_

Bee-louse or -tick, 520

Bees, 10 f.

Bees born of carcases, myth, 499

Bees' nest beetle, 235

Bees, stylopised, 300, 303

Beetles, 184 f.

Bellesme, on buzzing, 19

Belostomidae, 534, 565

Bembecidae, 482

Bembecides, 119 f.

_Bembex_, 509;

_B. rostrata_, 4, 120, 120 f.;

_B. spinolae_, 130 n.

Benchucha bug, 559

_Berosus_, 218

Berytidae, 548

_Bibio_, 475, 476, 477;

_B. marci_, 477

Bibionidae, 475

Birds and butterflies, 338

Biscuit-weevil, 247

_Bitoma crenata_, 233

_Bittacomorpha_, 473

Black-fly, 530

Blanchard, on flies attacking man, 517 n.

Blepharoceridae, 464

Blind beetles, 205, 221, 233

_Blissus leucopterus_, 548

Blister-beetles, 269

Blochmann, on founding new nests, 145

Blood-sucking, Diptera, 457;

Mosquitoes, 467

Blood-worms, 468

Blow-flies, 511

Blue-bottles, 511

Bogus Yucca-moth, 433

_Boletophila luminosa_, 463

Boll-worm, 416

Bombardier-beetles, 201

_Bombus_, 53 f.;

insect in nest of, 221;

fleas in nests of, 525;

parasite of, 94, 497;

proboscis of, 13 f., 14;

_B. agrorum_, 54;

_B. lapidarius_, 54;

_B. muscorum_, 57;

_B. variabilis_, 60

Bombyces, _367_

Bombycidae, _368_, 375, 406

Bombyliidae, 485

_Bombylius major_, 488

_Bombyx mori_, 375;

_B. yamamai_, 325

Book-worm, 247

Borboridae, _504_

_Borborus_, 505

_Borocera madagascariensis_, 405

Bostrichidae, 246

Bot-flies, 514

Brachelytra, _224_

Brachycera, 441, 454

Brachycerides, 291

Brachyscelides, 592, 598

_Brachytarsus_, 290

Braconidae, 590 {606}

_Bradypus cuculliger_, Tineid on, 430

Brahmaeidae, _368_, 374

Brain, 320;

cephalic and thoracic, 449

Branchiae, 208, 244

Brands, 332

Brassolides, 349

_Brathinus_, 223

Brauer, on Dipterous larvae, 451;

on Oestridae, 514

_Braula coeca_, 520

Braulidae, 520

Breastbone, 459

Breeze-flies, 443, 481

Breitenbach, on proboscis of Lepidoptera, 311 n.

Breithaupt, on proboscis of bee, 15;

on deglutition of bees, 18

Brenthidae, 295

_Brenthus anchorago_, 297

_Brephos notha_, 415, 416

Brimstones, 357

_Brontes planatus_, 234

Brown-tail moths, 407

Bruchidae, 276

_Bruchus fabae_ and _B. lentis_, 277, _B. pisi_, 277

_Bryophila_, 418

Buckell, on development of pattern, 335

Buffalo-gnats, 477

Bugong-moth, 417

Bugonia-myth, 499

Bull-dog ants, _171_, 173

Bull's-horn thorn and ants, 168

Bumble bee—see _Bombus_

Buprestidae, 261

_Buprestis attenuate_, supposed larvae of, 262 n.

Burgess, on suction, 311

Burnet-moths, 390

Burrows, of _Dasypoda_, 27;

of _Halictus_, 24, 25;

of _Odynerus_, 74

Bursa copulatrix, 321

Burying-beetles, 221

Butterflies, _341_ f.

Buzzing, 19

Byrrhidae, 242, _255_

_Byrrhus pilula_, 242

Bythoscopidae, 578

_Byturus_, _241_

_Cadphises moorei_, 391

Calandrides, 289

Calcium oxalate, 406

_Calicurgus_, 101;

_C. hyalinatus_, 102, 106

_Caligo eurylochus_, 350

_Callidea baro_, 303 n.

Callidulidae, _370_, 400

_Calliphora_; 448;

_C. erythrocephala_, _C. vomitoria_, 511

_Callirhipis dejeani_, 256

_Callomyia_, 496

_Callostoma fascipennis_, 489

_Caloptenus_, 270;

_C. italicus_, 489, _C. spretus_, 488, 506, enemies of

Calypter, calypterate, 448

Calyptrate Muscidae, 448, _504_

Camberwell Beauty, _352_

Camel bot-fly, 515

Camponotides, 144

_Camponotus_, 145;

_C. ligniperdus_, 138, 145, 147;

_C. pennsylvanicus_, 138, 146;

_C. rubripes_, 131;

_C. rufipes_, 137

Camptosomes, _279_, 281

Canephorinae, 394, 395

Cantharidae, 269 f.

Cantharides, _270_

Capsidae, 561

_Capsus laniarius_, 539

Carabidae, 204 f.

Carabides, _206_

Caraboidea, _190_, 200 f.

_Carcinocoris_, 554

Carder-bees, 45 f., 45

_Cardiocondyla_, 161

_Cardiophorus_, 258

Carlet, on sting, 6;

on sound-organs of _Cicada_, 574

Carnivora, _200_

Carotine, 549

Carpenter-bees, 33

Carpenter-worms, 395

Carpets, 411

_Carpocapsa juliana_, _C. pomonella_, _C. splendana_, _C. saltitans_, 428

_Carpophagus_, 278

_Carteria lacca_, 597

Carus, on paedogenesis, 461

_Caryoborus_, 278

Case, 281, 392, 393, 394, 417, 422, 423, 430, 431

Cassidides, _279_, 283

Caste-production, 142

_Castnia_, 307, 309, 316, 319;

_C. eudesmia_, _C. therapon_, 372

Castniidae, _369_, 371

_Castor canadensis_, parasite of, 219

_Cataclysta lemnata_, 423

Caterpillar, 322, 324, 325;

of Diptera, 474

_Catopomorphus_, 221

Cauda, 538, 588

Cave-beetles, 205, 221

Cebrionides, _260_

_Cecidipta excoecaria_, 424

_Cecidomyia buxi_, 459;

_C. destructor_, 460;

_C. tritici_, 460

Cecidomyiidae, 455 n., 458

_Cecropia_, plant and ants, 158

_Cedeocera_, 297 n.

Cell, of wing, 317, 318;

complete and incomplete, 116 n.

Cells, formation of, by bees, 21, 22, 24, 25, 28, 33, 34, 35, 46, 48, 51,

52, 54, 56, 60;

earthen, 72, 106;

of _Coelonites_, 89

Celyphidae, _504_ {607}

_Celyphus_, 505

_Cemonus unicolor_, 128

Cephaloidae, 275

_Cephalomyia maculata_, 515

_Cephaloon_, 275

Cephalothorax, 465;

of _Stylops_-larva, 302

_Cephenomyia rufibarbis_, 517

Cerambycidae, _278_, 285

Cerambycides, _287_

_Ceramius_, _89_;

_C. lusitanicus_, 89

_Ceranchia_, 374

_Cerapachys_, _175_ n.

_Ceratina_, 11, _32_

Ceratocampidae, _368_, 375

Ceratocombidae, 559

Ceratognathini, 194, _195_

_Ceratonema_, 401

_Ceratopogon_, 469;

_C. bipunctatus_, _C. pulicaris_, _C. varius_, 470

_Cerceris_, 125;

_C. arenaria_, 125;

_C. bupresticida_, 125;

_C. labiata_, 125;

_C. tuberculata_, 126

Cercopidae, 577

_Ceresa bubalus_, _C. taurina_, 577

_Cerocoma schaefferi_, 275

Cerophytides, _260_

_Ceroplastes ceriferus_, 597

_Ceroplatus mastersi_, 463

_Cerura vinula_, 383

Cervical sclerites, 472

_Cetonia_, in ants'-nests, 149;

_C. floricola_, 200

Cetoniides, _195_, 199

_Chaerocampa_, 380; recte _Choerocampa_

Chaetophorous, 446

Chaetotaxy, 446

Chafers, 194 f.

Chalcosiidae, 391, _420_

_Chalia hockingi_, 394

_Chalicodoma_, 32, 35;

_C. muraria_, 30, 35 f., 36, 254, 486;

_C. parietina_, _C. pyrenaica_, 39

Change of habit in larva, 301, 431

Chapman, Dr. T. A., on _Chrysis_, 3;

on classification of pupae of Lepidoptera, 367;

on _Hepialus_, 398;

on _Metoecus paradoxus_, 268;

on pupa of Lepidoptera, 327 n.

_Charagia_, 396

_Chartergus chartarius_, nest of, 82, 83

_Cheilosia chrysocoma_, 439

_Cheimatobia brumata_, 414

_Cheliomyrmex_, _180_

Chelonariides, 242

_Chelonia_, 410

_Chelostoma_, _35_

_Chennium bituberculatum_, 224

_Chermes_, 583, 586, 587;

_C. abietis_, 586, 587, 589

Cheshire, on proboscis of bee, 15

Chigger, 525

Child, on sense-organ, 442

China-marks, 421

Chinch-bug, 548

_Chionea araneoides_, 474

Chiromyzidae, 479

Chironomidae, 468, _474_

_Chironomus_, 440, 468

Chlamydes, _279_

_Chlorion_, 110ü

Chloropidae, _504_

_Chlorops_, 504

_Choerocampa elpenor_, 380

Choerocampini, 381

Cholodkovsky on _Chermes_, 586

_Choragus sheppardi_, 290

Chorion, 322

Chrysalis, 326, 344

Chrysauginae, 423

Chrysididae, 1 f.

_Chrysiridia madagascariensis_, 419

_Chrysis bidentata_, 3;

_C. ignita_, 3;

_C. shanghaiensis_, 4

_Chrysochus pretiosus_, 279

_Chrysocoris grandis_, 303 n.

Chrysomelidae, _276_, 278 f.

Chrysomelides, _279_

Chrysopolomidae, 396

_Chrysops_, 482

_Cicada_, 123;

_C. plebeia_, 574;

_C. septendecim_, 569

Cicadellinae, 578

Cicadidae, 568 f.

_Cicindela hybrida_, 202

Cicindelidae, 201 f.

_Cicinnus_, _378_ n.

_Cilix glaucata_ = _spinula_, 401

_Cimex_, _560_;

_C. lectularius_, 559

Cimicidae, 559

Cioidae, 245

_Cis melliei_, 245

Cistelidae, 264

_Cistus salvifolius_, beetle-larvae in, 282

_Cithaerias_, 348

_Citheronia_, 375

Cixiides, _576_

_Cixius_, 575

Clambidae, _223_

Clasper, 314

Classification, of ants, 144;

of bees, 20;

of butterflies, 341;

of Coleoptera, 189;

of Diptera, 454 f.;

of Hemiptera, 543;

of Hymenoptera Aculeata, _10_;

of Lepidoptera, 339 f.;

of moths, 366 f.

Clavicornia, _189_, _213_, 265

_Claviger testaceus_, 224

Clavigerides, 224

Clavus, 539

Clear-wings, 386

Cleggs, 481

_Cleosiris_, 400

_Cleptes_, 2, 4

Cleridae, 253

Click-beetles, 256 {608}

Clicking butterfly, 354

_Clidicus_, 223

_Clisiocampa neustria_, 322

Clothes-moths, 430

Clouded-yellows, 357

Clypeus, 307

_Clythra_ in ants'-nests, 149

Clythrides, _279_

_Cnemidotus caesus_, 209

_Cnethocampa processionea_, 376

Coarctate larva, 271

Coccidae, 592 f.;

destroyer of, 290

_Coccidula_, _239_

Coccinellidae, 237

_Coccus cacti_, 598;

_C. mannifera_, 597

Cochineal Insect, 598

Cochliopodidae, 402 n.

_Cochlophora_, 394

Cockchafer, 198

Cockroach, parasite of, 269

Cock-tail, 225

Cocoon, 46, 55, 66, 109, 122, 328, 347, 373, 376, 384, 385, 391, 403,

404, 405, 407, 419, 424, 436, 460, 462, 494;

flax-seed, 460;

of ants, 134;

aquatic, 280, 377

_Cocytia durvillii_, 382

Cocytiidae, 382

Codling-moth, 428

_Coelioxys_, 31

_Coelonites_, _89_;

_C. abbreviatus_, cells of, 89

_Coenomyia ferruginea_, 480

Coenomyiidae, 479

_Coenonympha_, 348

_Colaenis_, _351_

_Coleophora_, 431

Coleoptera, 184 f.

_Colletes_, 22;

_C. daviesanus_, 30

_Colobopsis_, 138

Colon, 320

Colorado beetle, 278

Colour, corresponding with locale, 201;

and surroundings, 337;

of larva and habits, 336;

of Sphingidae larvae, 381;

physiology of larval, 413;

of caterpillars and sex, 325;

development of, in Hemiptera, 542;

of eyes, 440

_Coluocera formicaria_, 240

Colydiidae, 233, 234

_Colydium_, 233

Comb, 63, 64, 65, 78, 79

Combs and brushes, 134

Compound pupa, 452

_Composmyia_, 512

Comstock, on nervures, 317 n.

Conchylidae, _427_

Connexivum, 538

Conopidae, 497, _504_

_Conorhinus sanguisuga_, 559

_Copiopteryx_, 373

_Copium clavicorne_, 550

_Copius_, 547

Copper butterflies, 356

Coprides, 195 f.

Coprini, _195_ n.

_Copris hispanus_, 197

Copulatory pouch, 320, 321

Cordyluridae, _504_

Coreidae, 546

_Corethra_, 467

Corium, 539

_Corixa_, 567

Corixidae, 567

Corn-leaves, larva on, 281

_Coronidia_, 419

_Corotoca_, 227

_Corticaria_, 240

Corylophidae, 228

Corynetides, 253

_Coscinocera hercules_, 372

Cossidae, _369_, 395

Cossonides, 294

_Cossus_, 309;

_C. ligniperda_, 319

Costal nervure, 318

Cotton-stainer bug, 548

Cotton-worm, 416

Courtship, 494;

of _Hepialus_, 398 f.

Coxa, 307

_Crabro_, 129;

_C. cephalotes_, 129;

_C. stirpicola_, 130 n.

Crabronides, 128 f.

Crambidae, 425

Crane-flies, 471

_Cratoparis_, 290

Cremaster, 327, 328, 344, 426

Cremastochilini, 200

_Cremastochilus_, 200

_Cremastogaster_, 165, 213;

_C. tricolor_, 165

Crepitation, 213, 214

Criocerides, _279_, 280

_Crioceris asparagi_, 281;

_C. merdigera_, 281

_Crossocerus_, 130;

_C. wesmaeli_, 130

Cryptocephalides, _279_

_Cryptocephalus_, _282_

Cryptocerata, _544_, 562 f.

Cryptocerini, 132, 134, 158, 159, 169

_Cryptocerus_, 138;

_C. atratus_, 170

Cryptophagidae, 235, _237_

_Cryptophagus dentatus_, 235

Cryptostomes, _279_, 282

_Cteniza ariana_, destroyer of, 490

_Ctenophora_, 475

Ctenostylidae, 517

Ctenuchinae, _409_

Cuckoo-bees, 22

Cuckoo-spit, 577

Cucujidae, _232_, 234

Cucujos, 258

Cuculinae, _20_

_Culex pipiens_, 466

Culicidae, 466 f.

Cultelli, 443

Cuneus, 539, 540 {609}

Cupesidae, 234

Curculionidae, 290

Curtice, on _Hypoderma_, 516

_Curupira_, 465

Cut-worms, 415

Cyathoceridae, 243

_Cybister laterimarginalis_ or _roeseli_, 210;

_C. tripunctatus_, 211

_Cybocephalus_, 232

Cyclica, _279_, 282

Cyclorrhapha, 454;

_C. Aschiza_, 455, 494 f.;

_C. Schizophora_, 456, 503 f.

_Cylidrus_, 253

Cylindrotomina, 474

Cymatophoridae, _368_, 386

Cymbidae, 410

_Cynomyia mortuorum_, 510

_Cyphagogus segnipes_, 296

_Cyphanta_, _368_ n.

_Cyphonia clavata_, 576

Cyphonidae, 255

Cyrtidae, 489

Cyrtocorides, 545

_Cyrtocoris monstrosus_, 546