vessels, which with their numerous ramifications may be pressed close
together, and drawn out considerably, but return immediately to their
usual size when the tension ceases; they creep under the skin close to
the spiracula, one at the right side of the insect, the other at the
left, each of them communicating with the air, by means of nine
spiracula; they are nearly as long as the body, beginning at the first
spiraculum, and going a little farther than the last, terminating in
some branches which extend to the extremities of the body. Round about
each spiraculum the tracheal artery pushes forth a great number of
branches, which are again divided into smaller ones; these further
subdivide, and spread through the whole body of the caterpillar. This
vessel and its principal branches are composed of three coats, which may
be separated one from the other. The exterior covering is a thick
membrane, furnished with a great number of fibres, which describe a vast
variety of circles round it, communicating with each other by numerous
shoots. The second is very thin and transparent; no particular vessel is
distinguished in it. The third is composed of scaly threads, which are
generally turned in a spiral form, and come so near each other, as
scarce to leave any interval; these threads are curiously united with
the membrane which occupies the intervals, and form a tube which is
always open, notwithstanding the flexure of the vessel. There are also
many other peculiarities in its structure, which cannot be well
explained without more plates. The principal tracheal vessels branch out
into 236 smaller ones, from which there spring 1326 different
ramifications.
The part of the caterpillar which naturalists call the HEART, without
being certain that it performs the functions thereof, is of a nature
very different from that of larger animals. It is almost as long as the
caterpillar itself, lies immediately under the skin at the top of the
back, entering into the head, and terminating near the mouth. It is
large and spacious towards the last rings of the body, and diminishes
very much as it approaches the head, from the fourth to the twelfth
division; it has on both sides, at each division, an appendage, which
partly covers the muscles of the back; but, growing narrower as it
approaches the lateral line, forms a number of irregular lozenge-shaped
bodies. This muscular tube has been called the heart of the caterpillar;
first, because it is generally filled with a kind of lymph, which has
been supposed to be the blood of the caterpillar; secondly, because in
all caterpillars, whose skin is in some degree transparent, continual,
regular, and alternate dilatations and contractions may be perceived
along the superior line, beginning at the eleventh ring, and going on
from ring to ring to the fourth, whence this vessel has been considered
as a file of hearts; but still this viscera seems to have very little
relation to the heart of larger animals; we find no vessel opening into
it, to answer to the aorta, vena cava, &c. &c. Near the eighth division
are two white oblong masses, that join the tube of the heart; they have
been called reniform bodies, because they are something similar to a
kidney in their shape.
The CORPUS CRASSUM is, with respect to volume, the most considerable
part of the whole caterpillar; it is the first and only substance that
is seen on opening it, forming a kind of sheath, which envelopes and
covers all the entrails, and introducing itself into the head, enters
all the muscles of the body, filling the greatest part of the empty
spaces in the caterpillar. It is of a milk-white colour. In its
configuration it is very similar to the human brain. When the different
masses of the corpus crassum which covers the entrails are removed, the
largest parts are the oesophagus, the ventricle, and the large
intestines.
The OESOPHAGUS descends from the bottom of the mouth to about the fourth
division. The anterior part which is in the head is fleshy, narrow, and
fixed by different muscles to the crustaceous parts thereof; the lower
part which passes into the body is wider, and forms a kind of
membranaceous bag, which is covered with very small muscles; near the
stomach it is again narrower, and is as it were bridled by a strong
nerve, which is fixed to it at distant intervals.
The VENTRICLE begins a little above the fourth division, where the
oesophagus finishes, and terminates at the tenth division; it is about
seven times longer than it is broad; the anterior part, which is the
broadest, is generally folded. The folds diminish with the bulk, in
proportion as it approaches the intestines. An assemblage of nerves
cover the surface, it is surrounded by a number of aerial vessels, and
opens into a tube, which Lyonet calls the large intestine.
There are three of these large tubes or INTESTINES, each of which
differs from the other so much, both in structure and character as to
require a particular name to distinguish them; though this is not the
place to enumerate these characteristic differences. As most
caterpillars are endued with a power or faculty of spinning, they are
provided with two vessels where the substance is prepared, which, when
drawn out, and extended in the air, becomes a silken thread; these two
vessels are termed the silk-vessels or tubes; in the caterpillar of the
cossus, they are often above three inches long, and are distinguished
into three parts, the anterior, the intermediate, and posterior. It has
also two other vessels, which are supposed to prepare and contain the
liquor by which it dissolves the wood on which it feeds.
Thus have we endeavoured to give the reader some idea of the wonderful
organization of this apparently imperfect animal. Assuredly the
four-thousand[100] muscles employed in the construction of the
caterpillar of the cossus cannot be considered without the deepest
astonishment: their admirable co-ordination and junction with other
parts equally numerous, yet all harmonizing and acting together as if
they were essentially one, naturally lead the mind to consider the
nature and perfection of creation, and to perceive that it is an
exhibition of the highest wisdom; and that this wisdom, which in the
minutest things gives evidence of such an immense attention to order and
use, has, no doubt, framed the whole for some great purpose; but what
that purpose is, exceeds the present limits of the human understanding
to discover.
[100] Lyonet sur la Chenille de Saule, p. 584.
A DESCRIPTION
OF
SUNDRY MISCELLANEOUS OBJECTS,
EXHIBITED
IN SEVERAL PLATES OF THIS WORK.
OF THE LEPAS ANATIFERA OR BARNACLE.[101]
Plate XIII. Fig. 1 and 2.
This is a tender and brittle shell-fish of a very peculiar species; its
length is about an inch, and its diameter about three quarters of an
inch. The shell is not composed of two pieces or valves, as in others,
but of five; two of these are larger than the rest, to which are affixed
two smaller ones; the fifth piece is long, slender, and crooked, running
down length-ways, and covering the joinings of the other pieces. The
shell part is of a pale red, variegated with white; it adheres to a neck
or pedicle of an inch long, and about a fifth of an inch in diameter; by
which means it affixes itself to old wood, to stones, to sea-plants, or
any other solid substance that lies under water. It can shorten or
extend this neck at pleasure, which resembles a small gut, and is
usually full of a glareous liquor; it is composed of two membranes, an
external one, hard and brown, an internal one, soft and of an orange
colour. The large portions of the shell open and shut in the manner of
the bivalves; the others, being moveable by means of their membranaceous
attachments, give way to the opening of these, and to the motions of the
body of the fish in any direction. It is furnished with a cluster of
filaments or tentacida, placed in a row on each side, usually twelve,
sometimes fourteen in number. They are a kind of arms appropriated for
catching its prey, and therefore placed so as to surround the mouth of
the animal, which is situated between them, and consequently easily
receives what they thrust towards it. By the motion of these arms, which
may be exerted in such a manner as to play either within or without the
cavity of the shell, it forms a current of water, which brings with it
the prey it feeds upon. Fig. 1 represents two of these arms as magnified
by the microscope; Fig. 2, the natural size of those from which these
drawings were made. Each arm consists of several joints, and each joint
is furnished on the concave side of the arm with a brush of fibrillæ or
long hairs. The arms, when viewed in the microscope, seem rather opake;
but they maybe rendered transparent, and form a most beautiful object,
by extracting out of the interior cavity a bundle of longitudinal
fibres, which runs the whole length of the arm. Mr. Needham[102] thinks
the motion and use of these arms illustrates the nature of that rotatory
motion which some writers have thought they discovered in the wheel
animal.
[101] This animal is classed by Linnæus among the Vermes Testaceæ. Its
generic character is: Animal, resembling a triton; Shell, consisting
of several unequal valves; affixed by its base. Specific character:
Pedunculated Barnacle, with compressed shell consisting of five
valves. Syst. Nat. p. 1107, 1109. EDIT.
[102] Needham’s Microscopical Observations.
In the midst of the arms is a hollow trunk, consisting of a jointed
fibrous or hairy tube, which incloses a long round tongue or proboscis,
that the animal can push occasionally out of the tube or sheath, and
retract at pleasure. The mouth of this animal is singular in its kind,
consisting of six laminæ, which go off with a bend, indented like a saw
on the convex edge, and by their circular disposition are so ranged,
that the teeth in the alternate elevation and depression of each plate,
act against whatever intervenes between them. The plates are placed
together in such a manner, that to the naked eye they form an aperture
not much unlike the mouth of a contracted purse.
The western isles of Scotland, and some other parts of the British
dominions, are abundantly stored, at certain times of the year, with a
bird of the goose kind, commonly known in those places by the name of
the brent goose or barnacle. These birds rarely breed with us, but seek,
for their sitting season, islands less frequented than those where we
find them in common. The seeing the birds so frequent, and yet never
finding any of their nests, induced ignorant people to believe they
never had any, and that they were not bred like other birds.
About the very shores where these birds are most common, the lepas
anatifera is also found in great abundance. The fishermen, who observed
vast quantities of these shells affixed to rotten wood, or dead trees
that were floating in the water, or lodged by it on the shore, were soon
led to imagine that the fibrous substances that hung out of them
resembled feathers, and persuaded themselves that the geese, whose
origin they could before by no means make out, were bred from them,
instead of being hatched, like other birds, from eggs.[103] It was
afterwards affirmed, that the shells themselves originally grew on the
trees, in the manner of their fruit; and that the young bird, having in
the shell obtained its plumage, dropt from thence into the water. From
this arose the opinion that the barnacle or brent goose was the produce
of a tree.[104]
[103] Hill’s Natural History of Animals.
[104] The absurd idea, that the brent goose or barnacle derived its
origin from this shell, was not confined to the illiterate; men of
science, incautiously confiding in the bold assertions of the
ignorant, appear to have given full credit to this truly curious
hypothesis, and disseminated the knowledge of it in their writings.
Even Gerard, the author of the Herbal, caught the infection: so
confident was he of the fact, that he invited the credulous to apply
to him for full satisfaction; his words are, “For the truth hereof, if
any do doubt, may it please them to repaire unto me, and I shall
satisfie them by the testimonie of good witnesses.” See his Herbal,
page 1587.
Barbut says, “This fabulous account originated from the sea-fowls,
when ready to lay their eggs, depositing them on the marine plants;
and, pecking sometimes these anatiferous shells, oblige the fish to
come out, which having devoured, they lay eggs in their place. The
young when hatched break through their prison, and fly away.” Genera
Vermium, Pars ii. page 13. EDIT.
OF THE LEUCOPSIS DORSIGERA.
Plate XVII. Fig. 1, 2, and 3.
This very beautiful and singular insect was first pointed out to me by
T. Marsham, Esq. Sec. L. S. who had seen it in the cabinet of insects
belonging to the Queen, in the royal observatory at Richmond. Her
Majesty was pleased to permit me to have the drawing taken from it, from
which this plate was engraved. When Mr. Marsham first saw it at
Richmond, he considered it as a non-descript insect, and an unique in
this country. But he has since found that it is mentioned by Fabricius,
in his Systema Entomologiæ, as a new genus under the name of leucospis
dorsigera. There is one of the insects in the cabinet of the celebrated
Linnæus, now in the possession of J. E. Smith, M. D. F. R. S. & Pr. L.
S. Sulz, and other writers, have also described it.
It appears at first sight like a wasp, to which genus the folded wings
would have given it a place, had not the remarkable sting or tube on the
back removed it from thence. It is probably a species between, and
uniting the sphex and wasp, in some degree partaking of the characters
of both. The antennæ are black and cylindrical, increasing in thickness
towards the extremity; the joint nearest the head is yellow, the head is
black, the thorax is also black, encompassed round with a yellow line,
and furnished with a cross one of the same colour near the head. The
scutellum is yellow, the abdomen black, with two yellow bands, and a
spot of the same colour on each side between the bands. A deep black
polished groove extends down the back, from the thorax to the anus, into
which the sting turns and is deposited, leaving the anus very circular;
a yellow line runs on each side the sting. The anus and the whole body,
when viewed with a shallow magnifier, appear punctuated; these points,
when examined in the microscope, appear hexagonal, as in the plate; and
in the center of each hexagon a small hair is to be seen; the feet are
yellow, the hinder thighs very thick and dentated, forming also a groove
for the next joint; they are yellow with black spots. This insect is
found in Italy, Switzerland, France, and Germany. Fig. 1 shews it very
much magnified; Fig. 2 is a side view of it less magnified; Fig. 3 is
the object of its real size.
OF THE LOBSTER INSECT.
Plate XVIII. Fig. 1 and 6.
This extraordinary little creature was found by my ingenious friend, Mr.
John Adams, of Edmonton; he was at the New Inn, Waltham Abbey, where it
was spied by some labouring men who were drinking their porter. The man
who first perceived it, thought it was of an uncommon form; on a more
minute inspection, it was supposed to be a louse with unusual long
horns; others thought it was a mite. This produced a debate, which
attracted the attention of my friend, who obtained the insect from them
for further observation. Mr. Martin has given some account of it in the
third volume of “The Young Gentleman and Lady’s Philosophy.” Mr. Adams
favoured me with the insect, that an accurate drawing might be taken
from it, which I thought would be highly pleasing not only to the lovers
of microscopic observations, but also to the entomologist. It appears to
be quite a distinct species from the phalangium cancroides of Linnæus,
of which a good drawing has been given by Hooke, Rösel, Schæffer, &c.;
it has also been described by Scopoli, Geoffroy, and other naturalists;
not one, however, of these descriptions agrees with the animal under
consideration. The abdomen of this is more extended, the claws are
larger and much more obtuse; the body of the other being nearly
orbicular, the claws slender, and finishing almost in a point, more
transparent, and of a paler colour. It is very probable, that there are
several species nearly similar. Mr. Marsham has two in his possession,
one like the drawings of Reaumur, the other not to be distinguished from
that which is represented in the plate, except that it wants the break
or dent in the claws, so conspicuous in this. The latter he caught on a
flower in Essex, the first week in August, firmly affixed by its claws
to the thigh of a large fly, and could not disengage it from thence
without considerable difficulty; to accomplish which, he was obliged to
tear off the fly’s leg, and was much surprized to see the bold little
creature spring forward full a quarter of an inch, and once more seize
its prey, from which he again found it very difficult to disengage it.
Fig. 1 represents the insect considerably magnified, Fig. 6 the natural
size.[105]
[105] According to Aldrovandus, this insect was not unknown to
Aristotle, who mentions it as being found in books and paper.
Wolphius, on the authority of Gesner, says that a few are to be met
with in some parts of Switzerland. Scaliger also notices it, having
found two of them in his books. It has been by various systematic
writers referred to different genera; De Geer has instituted a new
genus for it under the name of chelifer; Fabricius has remanded it to
that of scorpio, to which perhaps it is more nearly allied than any
other.
Amongst the number of naturalists who have observed and described the
insect, it appears rather extraordinary that none have met with one
similar to that in the plate, in respect to the break in the claws. In
a cabinet of curious microscopic objects which I purchased several
years since, and which originally came from Holland, there were four
of them in the most perfect condition. A botanical friend, Mr. Young,
also favoured me with a living one which he found among some plants
collected by him in one of his excursions; but, as his box contained a
variety of plants, and he did not discover the insect till his return,
it was impossible to ascertain the particular one on which it was
taken. All these resembled the one here exhibited, excepting the claws
being longer and more slender, and being deficient in the
distinguishing characteristic; I have lately seen another, in which
the two fangs that are shewn highly magnified in Plate 85 of the
Naturalist’s Miscellany, are very apparent, being so large, as to
exceed in diameter the thickest part of the claws.
My respectable friend, Matthew Yatman, Esq. informs me, that some
years since one was found on a bottle of wine packed in saw-dust, at
the house in which he then resided in Percy street; on putting the
point of a pin towards it to remove it from the bottle, it ran
backward, put itself into an attitude of defence, and opened its claws
as meditating vengeance. In the same cellar one had many years
previous been discovered, sufficiently large to admit its being
fastened to a card with thread by a young gentleman, being at least
four times the usual size.
Rösel says it dwells among paper, in old books and their bindings, in
chests of drawers, and in the crevices of old buildings. In order to
discover whether the insect possessed a sting, he often by various
means endeavoured to irritate it; but it never shewed the smallest
inclination to defend itself, on the contrary, it always endeavoured
to avoid a contest; if so, it evidently appears that those few met
with in this country are of a more bold and warlike disposition.
Seba asserts that these insects resemble the large scorpions, the tail
excepted, which is small, and usually concealed by being drawn close
to the under part of the abdomen; but in this respect he must probably
have been mistaken, as it does not appear that this circumstance has
been noticed by any other person. EDIT.
OF THE THRIPS PHYSAPUS.
Plate XVIII. Fig. 3, 4, and 5.
The insect, which is represented very considerably magnified at Fig. 3,
is of the hemiptera class. It was first described and figured by De Geer
in the Swedish Transactions for 1744, under the name of physapus ater,
alis albis; Linnæus afterwards introduced it in a subsequent edition of
the Systema Naturæ distinguished by the name thrips physapus.
These insects live upon plants, and particularly in flowers. The one
figured here is the black thrips, with white wings; the antennæ have six
articulations; the body is black; the wings whitish, long, and hairy;
the head small, with two large reticular eyes. The antennæ are of an
equal size throughout, and divided into six oval pieces which are
articulated together. The extremities of the feet are furnished with a
membranaceous and flexible bladder, which it can throw out and draw in
at pleasure. It places and presses this bladder against the substances
on which it is walking, and seems to fix itself thereby to them; the
bladder sometimes appears concave towards the bottom, the concavity
increasing or diminishing in proportion to the degree of pressure.
They have four wings, two upper and two under ones; these last are with
great difficulty perceived, they are fixed to the upper part of the
breast, lying horizontally; both of them are rather pointed towards the
edges, and have a strong nerve running round them, which is set with a
fringe of fibrillæ, tufted at the extremity. The wings are represented
by themselves at Fig. 4; the insect of the real size at Fig. 5. They are
to be found in great plenty in the spring and summer, in the flowers of
the dandelion, and various other plants.
OF THE SKIN OF THE LUMP SUCKER.
Plate XVIII. Fig. 2 and 7.
For a full description of this singular fish, I must refer the reader to
Pennant’s British Zoology, vol. iii. p. 117. The Linnean name is
cyclopterus lumpus. Fig. 2 is a piece of the skin highly magnified:
there are no scales on the body, but a great number of tubercles, which
are here exhibited. Fig. 7 is the natural size of the object.
These fishes being extremely fat, renders them an agreeable diet to the
natives of Greenland, in which seas they abound in the months of April
and May; they also resort in multitudes during spring to the coast of
Sutherland, near the Ord of Caithness in North Britain, where the seals
prey greatly upon them, leaving the skins; numbers of which thus emptied
float at that season ashore. When a good specimen is procured, it forms
a most beautiful object for the opake microscope.
OF THE CIMEX STRIATUS.
Plate XX. Fig. 1 and A.
This is a beautiful insect of the hemiptera class, or that kind where
the elytra are only in part crustaceous, and which do not form a
longitudinal suture down the back, but fold over about one-third of
their length toward the bottom, where it is also partly transparent. It
is of the genus cimex, and called striatus by Linnæus. Its colours are
bright and elegantly disposed: the head, proboscis, and thorax are
black. The thorax is ornamented with yellow spots, the middle one
large, and occupying almost one-third of the posterior part; the other
two are on each side, and triangular. The scutellum has two yellow
oblong spots, pointed at each end; the ground of the elytra is a bright
yellow, spotted and striped with black. The nerves are yellow, and there
is a brilliant triangular spot of orange, which unites the crustaceous
and membranaceous parts; the latter is brown and clouded. The feet are
of a fine red, and the rings of the abdomen are black, edged with white.
This pretty insect is to be found in June, upon the elm-tree. It is
represented at A of the natural size.
OF THE CHRYSOMELA ASPARAGI.
Plate XX. Fig. 2 and B.
A very common, though elegant insect of the coleoptera class, is
represented at Fig. 2, as seen in the lucernal microscope, and of its
natural size at B; it is called by Linnæus chrysomela asparagi, from the
larva feeding on the leaves of that plant. Its shape is oblong, the
antennæ black, composed of many joints nearly oval. The head is of a
bright, but deep blue; the thorax red and cylindrical; the elytra blue,
with a yellow margin, and three spots of the same colour on each, one at
the base of an oblong form, and two united with the margin; the legs are
black, but the under side of the belly is of the same blue colour with
the elytra and head. This little animal, when viewed by the naked eye,
scarcely appears to deserve any notice; but when examined by the
microscope, is one of the most pleasing opake objects we have. It is
found in June, on the asparagus after it has run to seed. De Geer says,
that it is very scarce in Sweden.
OF THE MELOE MONOCEROS.
Plate XX. Fig. 3 and C.