attack a cheese wherever deposited; but when we learn from Leeuwenhoek,
that one lived eleven weeks gummed on its back to the point of a needle
without food, our wonder will be diminished[314]. Another species
of mite (_Uropoda vegetans_) was observed by De Geer to live some
time in spirits of wine[315]. This last circumstance reminds me of an
event which befel myself, that I cannot refrain from relating to you,
since it was the cause of my taking up the pursuit I am recommending
to you. One morning I observed on my study window a little lady-bird
yellow with black dots (_Coccinella_ 22-_punctata_)--"You are very
pretty," said I to myself, "and I should like to have a collection
of such creatures." Immediately I seized my prey, and not knowing
how to destroy it, I immersed it in geneva. After leaving it in this
situation a day and a night, and seeing it without motion, I concluded
it was dead, and laid it in the sun to dry. It no sooner, however, felt
the warmth than it began to move, and afterward flew away. From this
time I began to attend to insects.--The chamæleon-fly (_Stratyomis
Chamæleon_) was observed by Swammerdam to retain its vital powers
after an immersion equally long in spirits of wine. Gœdart affirms
that this fly, on which account it was called chamæleon, will live
nine months without food; a circumstance, if true, more wonderful than
what I formerly related to you with respect to one of the aphidivorous
flies[316].--If insects will escape unhurt from a bath of alcohol, it
may be supposed that one of water will be less to be dreaded by them.
To this they are often exposed in rainy weather, when ruts and hollows
are filled with water: but when the water is dried up, it is seldom
that any dead carcases of insects are to be seen in them. Mr. Curtis
submerged the fragile aphides for sixteen hours; when taken out of the
water they immediately showed signs of life, and out of four, three
survived the experiment:--an immersion of twenty-four hours, however,
proved fatal to them[317].
The late ingenious, learned, and lamented Dr. Reeve of Norwich
once related to me that he found in a hot fountain on the top of
a mountain, near Leuk in the Valais in Switzerland, in which the
thermometer stood at 205°, transparent larvæ, probably of gnats, or
some such insect.--Lord Bute also, in a letter to my late revered
friend, the Rev. William Jones of Nayland, imparts a similar
observation made by His Lordship at the baths of Abano, near the
Euganian mountains, on the borders of the Paduan states. They are
strong, sulphureous, boiling springs, oozing out of a rocky eminence
in great numbers, and spreading over an acre of the top of a gentle
hill. In the midst of these boiling springs, within three feet
of five or six of them, rises a tepid one about blood warm. But
the most extraordinary circumstance which he relates is, that not
only confervas were found in the _boiling_ springs, but numbers of
small black beetles, that died upon being taken out and plunged
into cold water[318].--And once, having taken in the hot dung of my
cucumber-bed a small beetle (_Synchita Juglandis_), I immersed it
in boiling water; and after keeping it submerged a sufficient time,
as I thought, to destroy it, upon taking it out, and laying it to
dry, it soon began to move and walk. Its native station being of
so high a temperature, Providence has fitted it for it, by giving
it extraordinary powers of sustaining heat. Other insects are as
remarkable for bearing any degree of cold. Some gnats that De Geer
observed, survived after the water in which they were was frozen into
a mass of ice: and Reaumur relates many similar instances[319].
The last passive means of defence that I mentioned, was the
_multiplication_ of insects. Some species, the Aphides for instance,
and the Grasshoppers and Locusts, have such an infinite host of
enemies, that were it not for their numbers the race would soon
be annihilated.--But as passive means of defence have detained us
sufficiently long, it is enough to have touched upon this head. Let
us then now proceed to such as may be called active; in which the
volition of the animal bears some part.
II. The _active_ means of defence, which tend to secure insects from
injury or attack, are much more numerous and diversified than the
passive; and also more interesting, since they depend, more or less,
upon the efforts and industry of these creatures themselves. When
urged by danger, they endeavour to repel it either by having recourse
to certain attitudes or motions; producing particular noises;
emitting disagreeable scents or fluids; employing their limbs; or
weapons, and valour; concealing themselves in various ways; or by
counteracting the designs and attack of their enemies by contrivances
that require ingenuity and skill.
The _attitudes_ which insects assume for this purpose are various.
Some are purely imitative, as in many instances detailed above. I
possess a diminutive rove-beetle (_Aleochara complicans_, K. Ms.) to
which my attention was attracted as a very minute, shining, round,
black pebble. This successful imitation was produced by folding its
head under its breast, and turning up its abdomen over its elytra;
so that the most piercing and discriminating eye would never have
discovered it to be an insect.--I have observed that a carrion beetle
(_Silpha thoracica_) when alarmed has recourse to a similar manœuvre.
Its orange-coloured thorax, the rest of the body being black,
renders it particularly conspicuous. To obviate this inconvenience,
it turns its head and tail inwards till they are parallel with the
trunk and abdomen, and gives its thorax a vertical direction, when
it resembles a rough stone.--The species of another genus of beetles
(_Agathidium_) will also bend both head and thorax under the elytra,
and so assume the appearance of shining globular pebbles.
Related to the defensive attitude of the two last-mentioned insects,
and precisely the same with that of the Armadillo (_Dasypus_) amongst
quadrupeds, is that of one of the species of woodlouse (_Armadillo
vulgaris_). This insect when alarmed rolls itself up into a little
ball. In this attitude its legs and the underside of the body, which
are soft, are entirely covered and defended by the hard crust that
forms the upper surface of the animal. These balls are perfectly
spherical, black, and shining, and belted with narrow white bands, so
as to resemble beautiful beads; and could they be preserved in this
form and strung, would make very ornamental necklaces and bracelets.
At least so thought Swammerdam's maid, who, finding a number of these
insects thus rolled up in her master's garden, mistaking them for
beads, employed herself in stringing them on a thread; when to her
great surprise, the poor animals beginning to move and struggle for
their liberty, crying out and running away in the utmost alarm she
threw down her prize[320].--The golden-wasp tribe also, (_Chrysis_
and _Parnopes_,) all of which I suspect to be parasitic insects, roll
themselves up, as I have often observed, into a little ball when
alarmed, and can thus secure themselves--the upper surface of the
body being remarkably hard, and impenetrable to their weapons--from
the stings of those _Hymenoptera_ whose nests they enter with the
view of depositing their eggs in their offspring. Latreille noticed
this attitude in _Parnopes carnea_, which, he tells us, _Bembex
rostrata_ pursues, though it attacks no other similar insect, with
great fury; and, seizing it with its feet, attempts to dispatch it
with its sting, from which it thus secures itself[321].
Other insects endeavour to protect themselves from danger by
simulating death. The common dung-chafer (_Geotrupes stercorarius_)
when touched, or in fear, sets out its legs as stiff as if they were
made of iron-wire--which is their posture when dead--and remaining
perfectly motionless, thus deceives the rooks which prey upon them,
and like the ant-lion before celebrated[322] will eat them only when
alive. A different attitude is assumed by one of the tree-chafers
(_Hoplia pulverulenta_) probably with the same view. It sometimes
elevates its posterior legs into the air, so as to form a straight
vertical line, at right angles with the upper surface of its
body.--Another genus of insects of the same order, the pill-beetles
(_Byrrhus_), have recourse to a method the reverse of this. They
pack their legs, which are short and flat, so close to their body,
and lie so entirely without motion when alarmed, that they look like
a dead body, or rather the dung of some small animal.--Amongst the
weevil tribe, most of the species of Germar's genus _Cryptorynchus_,
including several modern genera or subgenera, when an entomological
finger approaches them, as I have often experienced to my great
disappointment, applying their rostrum and legs to the underside of
their trunk, fall from the station on which you hope to entrap them,
to the ground or amongst the grass; where, lying without stirring
a limb, they are scarcely to be distinguished from the soil around
them. Thus also, doubtless, they often disappoint the birds as
well as the entomologist.--A little timber-boring beetle (_Anobium
pertinax_), (and others of the genus have the same faculty,)
which, when the head is withdrawn somewhat within the thorax, much
resembles a monk with his hood, has long been famous for a most
pertinacious simulation of death. All that has been related of the
heroic constancy of American savages, when taken and tortured by
their enemies, scarcely comes up to that which these little creatures
exhibit. You may maim them, pull them limb from limb, roast them
alive over a slow-fire[323], but you will not gain your end; not a
joint will they move, nor show by the least symptom that they suffer
pain. Do not think, however, that I ever tried these experiments upon
them myself, or that I recommend you to do the same. I am content
to believe the facts that I have here stated upon the concurrent
testimony of respectable witnesses, without feeling any temptation
to put the constancy of the poor insect again to the test.--A similar
apathy is shown by some species of saw-flies (_Serrifera_), which
when alarmed conceal their antennæ under their body, place their
legs close to it, and remain without motion even when transfixed
by a pin.--Spiders also simulate death by folding up their legs,
falling from their station, and remaining motionless; and when in
this situation, they may be pierced and torn to pieces without their
exhibiting the slightest symptom of pain[324].
There is a certain tribe of caterpillars called surveyors (_Geometræ_),
that will sometimes support themselves for whole hours, by means of
their posterior legs, solely upon their anal extremity, forming an
angle of various degrees with the branch on which they are standing,
and looking like one of its twigs. Many concurring circumstances
promote this deception. The body is kept stiff and immoveable with
the separations of the segments scarcely visible; it terminates in a
knob, the legs being applied close, so as to resemble the gem at the
end of a twig; besides which, it often exhibits intermediate tubercles
which increase the resemblance. Its colour too is usually obscure,
and similar to that of the bark of a tree. So that, doubtless, the
sparrows and other birds are frequently deceived by this manœuvre, and
thus balked of their prey. Rösel's gardener, mistaking one of these
caterpillars for a dead twig, started back in great alarm when upon
attempting to break it off he found it was a living animal[325].
But insects do not always confine themselves to attitudes by which
they meditate escape or concealment; they sometimes, to show their
courage, put themselves in a posture of defence, and even have in
view the annoyance as well as the repelling of their foes. The
great rove-beetle (_Goerius olens_) presents an object sufficiently
terrific, when with its large jaws expanded, and its abdomen turned
over its head, like a scorpion, it menaces its enemies, some of which
this ferocious attitude may deter from attacking it. Mr. Bingley
informs us that the giant earwig (_Labidura gigantea_), a rare
species that his researches have added to the catalogue of British
insects, turns up over its head, in a similar manner, its abdomen,
which being armed at the end with a large forceps must give it an
appearance still more alarming[326].
The caterpillars of some hawk-moths (_Sphinx_), particularly that which
feeds upon the privet, when they repose, holding strongly with their
prolegs the branch on which they are standing, rear the anterior part
of their body so as to form nearly a right angle with the posterior;
and in this position it will remain perfectly tranquil,--thus eluding
the notice of its enemies, or alarming them,--perhaps for hours.
Reaumur relates that a gardener in the employment of the celebrated
Jussieu used to be quite disconcerted by the self-sufficient air
of these animals, saying they must be very proud, for he had never
seen any other caterpillars hold their head so high[327]. From this
attitude, which precisely resembles that which sculptors have assigned
to the fabulous monster called by that name, the term _Sphinx_ has been
used to designate this genus of insects.--The caterpillar of a moth
(_Lophopteryx camelina_) noticed by the author just quoted, whenever
it rests from feeding, turns its head over its back, then become
concave, at the same time elevating its tail, the extremity of which
remains in a horizontal position, with two short horns like ears behind
it. Thus the six anterior legs are in the air, and the whole animal
looks like a quadruped in miniature; the tail being its head--the horns
its ears--and the reflexed head simulating a tail curled over its
back[328]. In this seemingly unnatural attitude it will remain without
motion for a very long time.
Some lepidopterous larvæ, that fix the one half of the body and
elevate the other, agitate the elevated part, whether it be the head
or the tail, as if to strike what disturbs them[329]. The giant
caterpillar of a large North American moth (_Ceracampa regalis_) is
armed behind the head and at the back of the anterior segments with
seven or eight strong curved spines from half to three-fourths of an
inch in length. Mr. Abbot tells us that this caterpillar is called
in Virginia the hickory-horned devil, and that when disturbed it
draws up its head, shaking or striking it from side to side; which
attitude gives it so formidable an aspect, that no one, he affirms,
will venture to handle it, people in general dreading it as much as
a rattle-snake. When, to convince the Negroes that it was harmless,
he himself took hold of this animal in their presence, they used
to reply that it could not sting him, but would them[330]. The
species of a genus of beetles named _Malachius_, endeavour to alarm
their enemies and show their rage by puffing out and inflating four
vesicles from the sides of their body, which are of a bright red,
soft, and of an irregular shape. When the cause of alarm is removed,
they are retracted, so that only a small portion of them appears[331].
Insects often endeavour to repel or escape from assailants by their
_motions_. Mr. White, mentioning a wild bee that makes its nest on
the summit of a remarkable hill near Lewes in Sussex, in the chalky
soil, says: "When people approach the place these insects begin to
be alarmed, and with a sharp and hostile sound dash and strike round
the heads and faces of intruders. I have often been interrupted
myself while contemplating the grandeur of the scenery around me, and
have thought myself in danger of being stung[332]."--The hive-bee
will sometimes have recourse to the same expedient, when her hive is
approached too near, and thus give you notice what you may expect if
you do not take her warning and retire.--Humble-bees when disturbed,
whether out of the nest or in it, assume some very grotesque and at
the same time threatening attitudes. If you put your finger to them,
they will either successively or simultaneously lift up the three
legs of one side; turn themselves upon their back; bend up their anus
and show their sting accompanied by a drop of poison. Sometimes they
will even spirt out that liquor. When in the nest, if it be attacked,
they also beat their wings violently and emit a great hum[333].
These motions menace vengeance; those of some other insects are
merely to effect their escape. Thus I have observed that the species
of the May-fly tribe (_Trichoptera_[334]), when I have attempted to
take them, have often glided away from under my hand--without moving
their limbs that I could discover--in a remarkable manner. I once
observed a short-snouted weevil (_Brachyrhynchus_, Schön.) upon a
rail, which, when it saw me, slided sideways, and then rolled off.
To notice the ordinary motions of insects, which are often means by
which they escape from danger, would here be premature, since they
will be fully considered in a subsequent letter. I shall therefore
only mention the zigzag flight of butterflies and the traverse
sailing of humble-bees, which certainly render it more difficult for
the birds to catch them while on the wing.
_Noises_ are another mean of defence to which insects have occasional
recourse. I have heard the lunar dung-beetle (_Copris lunaris_) when
disturbed utter a shrill sound. _Dynastes Oromedon_, another of
the lamellicorn insects, was observed by Dr. Arnold to make, when
alarmed, a kind of creaking noise, which it produced by rubbing
its abdomen against its elytra. A third of the same tribe, (_Trox
sabulosus_) emits a small sibilant or chirping noise, as I once
observed when I found several feeding in a ram's horn. The "drowsy
hum" of beetles, humble-bees, and other insects, in their flight,
may tend to preserve them from some of their aërial assailants.
And the angry chidings of the inhabitants of the hive, which are
very distinguishable from their ordinary sounds, may be regarded as
warning voices to those from whom they apprehend evil or an attack.
I have before observed that the death's-head hawk-moth (_Acherontia
Atropos_), when menaced by the stings of ten thousand bees enraged
at her depredations upon their property, possesses the secret to
disarm them of their fury[335]. This insect, when in fear or danger,
is known to produce a sharp, shrill, mournful cry, which with the
superstitious has added to the alarm produced by the symbol of death
which signalizes its thorax[336]. This cry, there is reason to
believe, affects and disarms the bees, so as to enable her to proceed
in her spoliations with impunity[337]. One of these insects being
once brought to a learned divine, who was also an entomologist, when
he was unwell, he was so much moved by its plaintive noise, that,
instead of devoting it to destruction, he gave the animal its life
and liberty. I might say more upon this subject of defensive noises:
but I shall reserve what I have further to communicate, to a letter
which I purpose devoting to the sounds produced or emitted by insects.
You are acquainted with the singular property of the skunk (_Viverra
putorius_, L.), which repels its assailants by the fetid vapour that
it explodes; but perhaps are not aware that the Creator has endowed
many insects with the same property and for the same purpose--some of
which exhale powerful or disagreeable _odours_ at all times, and from
the general surface of their body; while they issue from others only
through particular organs, and when they are attacked.
Of the former description of defensive scents there are numerous
examples in almost every order; for, next to plants and vegetable
substances, insects, of any part of the creation, afford the
greatest diversity of odours. In the _Coleoptera_ order a very
common beetle, the whirlwig (_Gyrinus Natator_), will infect your
finger for a long time with a disagreeable rancid smell; while two
other species, _G. minutus_ and _villosus_, are scentless.--Those
unclean feeders, the carrion beetles (_Silpha_, L.), as might be
expected from the nature of their food, are at the same time very
fetid.--Pliny tells us of a Blatta,--which, from his description,
is evidently the darkling-beetle (_Blaps mortisaga_), and which he
recommends as an infallible nostrum, when applied with oil extracted
from the cedar, in otherwise incurable ulcers,--that was an object
of general disgust on account of its ill scent, a character which it
still maintains[338].--Numbers of the ground-beetles (_Eutrechina_)
that are found under stones, and in places that have not a free
circulation of air, exhale a most disagreeable and penetrating odour,
which De Geer observes resembles that of rancid butter, and is not
soon got rid of. It is produced, he says, from an unctuous matter
that transpires through the body[339]; but I am rather inclined to
think it proceeds from the extremity.--I have noticed that some
small beetles of the _Omalium_ genus--for instance _O. rivulare_,
and another species that I once found in abundance on the primrose
(_O. Primulæ_, K. Ms.), especially the latter--are abominably fetid
when taken, and that it requires more than one washing to free
the fingers from it. Every one knows that the cock-roach (_Blatta
orientalis_), belonging to the _Orthoptera_ order, is not remarkable
for a pleasant scent;--but none are more notorious for their bad
character in this respect than the bug tribe (_Geocorisæ_), which
almost universally exhale an odour that mixes with the scent of
cucumbers another extremely unpleasant and annoying. Some however
are less disgusting, particularly _Lygæus Hyoscyami_, which
yields, De Geer found, an agreeable odour of thyme[340].--Several
lepidopterous larvæ are defended by their ill smell; but I shall
only particularize the silk-worms, which on that account are said
to be unwholesome.--_Phryganea grandis_, a kind of May-fly, is a
_trichopterous_ insect that offends the nostrils in this way; but
a worse is _Chrysopa Perla_, a golden-eyed and lace-winged fly, of
the next order, whose beauty is counterbalanced by a strong scent of
human ordure that proceeds from it.--Numberless _Hymenoptera_ act
upon the olfactory nerves by their ill or powerful effluvia. One of
them, an ant _(Formica fœtida_ De Geer, _fœtens_ Oliv.), has the same
smell with the insect last mentioned[341]. Our common black ant (_F.
fuliginosa_), whose curious nests in trees have been before described
to you[342], is an insect of a powerful and penetrating scent,
which it imparts to every thing with which it comes in contact;
and Fabricius distinguishes another (_F. analis_, Latr., _fœtens_,
F.) by an epithet (_fœtidissima_) which sufficiently declares its
properties. Many wild bees (_Andrena_) are distinguished by their
pungent alliaceous smell. _Crabro U. flavum_, a wasp-like insect, is
remarkable for the penetrating and spirituous effluvia of ether that
it exhales[343]. Indeed there is scarcely any species in this order
that has not a peculiar scent.--Some dipterous insects--though these
in general neither offend nor delight us by it--are distinguished by
their smell. Thus _Mesembrina mystacea_, a fly that in its grub state
lives in cow-dung, savours in this respect, when a denizen of the
air, of the substance in which it first drew breath[344]. And another
(_Sepsis cynipsea_,) emits a fragrant odour of baum[345].--I have not
much to tell you with respect to apterous insects, except that _Iulus
terrestris_, a common millepede, leaves a strong and disagreeable
scent upon the fingers when handled[346]. Most of the insects I have
here enumerated, probably, are defended from some enemy or injury by
the strong vapours that exhale from them; and perhaps some in the
list produce it from particular organs not yet noticed.