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7. Vntrnn.%. Aristatae, furnished with a lateral hair, as in the lly.S, 9. a Caput, the head . I> Palpi, the feelers, c Antennae, orhorns, d Oculi, the eyes, r Thorax. /Scutellum, or es-cutcheon. g Pectus, the breast, h Sternum, the breast-bone. i Abdomen, and its segments. k Anus . I Elytra,or shells, m Membranous wings, n Pedes, the feet, whichare natatorii.
10. o Femur, the thigh, p Tibia, or leg. q Tarsus, or foot, rUnguis , or claw.
11 .a The anterior part of the wing, b The posterior part. cTheexterior part. d. The interior part, e The margin. /'Thedisk, or middle, g Oculus, the eye.
IS, 13, 14, 15, Represent the insect in its egg, caterpillar, pupa,and perfect state.
Of the Metamorfhoses of Insects.
All insects, except those of the aptera order, are continually un-dergoing some transformation. Insects change first from the (ovum)egg, into the (larva) caterpillar or maggot; then into the (pupa)chrysalis ; and lastly into the (imago) fly, or perfect state.D uriug each of these changes, their appearance differs as much asnight and day. The insect, as soon as it came out of the egg, wasby former entomologists called eruca ; but as this is synonymouswith the botanic name sisymbrium, it was changed by Linnaeus for the term.
Larva; a name expressive of the insect’s being, in this state,as it were, masked, having its true appearance concealed. Under thismask of skin the entire insect, such as it afterwards appears whenperfect, lies concealed, enveloped only in its tender wings, andputting on a soft and pulpy appearance; insomuch that Swammer-dam was able to demonstrate the butterfly w ith its wings to existin a caterpillar, though it bore but a faint resemblance to its futureperfection. The insect, therefore, in this state, undergoes littleother alteration but the change of its skin. The larva; are, for themost part, larger than the insect when perfect, and are very vora-cious. The caterpillar of the cabbage butterfly eats double whatit would seem to require from its size ; but its growth is not ade-quate to its voracity.
Pupa . The insect in this state was formerly called chrysalis oraurelia: but as the appearance of gilding is confined to a few but-terflies only, the term of pupa has been adopted in its stead; be-cause the lepidoptera, especially, resemble an infant in swaddlingclothes; and in this state all, except those of the hemiptera class,take no nourishment.
Imago is the third state. This name is given by Linnxus tothis third change, in which the insect appears in its proper shape andcolours: and as it undergoes no more transformations, it is calledperfect. In this state it flies, is capable of propagating its species,and receives true antenna;; which before, in most insects, werescarce apparent. As the shape of the pupa is different in differentinsects, it assumes different names; thus it is called,
Coakctata, when it is round, and as it were turned, withoutthe least resemblance of the structure of the insect; as in thediptera.
Obtecta, when it consists as it were of two parts, one of whichsurrounds the head and thorax, and the other the abdomen.
Incompleta, w’hen they have wings and feet, but are notcapable of moving them ; as in most of the hymenoptera.
Semicomplkta, in which they walk or run, but have only therudiments of wings.
Lompleta, in which they immediately obtain the perfect formot the insect, without undergoing anymore change: as in thoseof the aptera class, except only the flea. The bed bug also be-longs to this class. 'I'he spider undergoes frequent transformations,though only in the colour of its skin. The crustaceous insects, as
crabs, lobsters, &c. yearly cast their shells, as their growth wouldotherwise be impeded. The scolopendri, when young, havefewer feet than when they are full grown. All insects, as soon asthey undergo the third change, are arrived at their full growth ;nor do we find any difference in the size of the same species of in-sect in the same countries, unless, during its caterpillar state, it hasnot had a sufficiency of proper food.
Of the Orders of Insects.
The class of Insects is divided by 1 dunams into seven orders:
1. The Coleoptera [frolb *»».«;, a sheath, and w7^ov, a w ing,]are such insects as have crustaceous elytera or shells, which shuttogether, and form a longitudinal suture down the back of the in-sect ; as the beetle, bupcalris ignita, Piale XXXVII. tig. 16.
2. Hemiptera [from ’ii-aw, half, and wltgov,] have their upperwings usually half crustaceous and half membranaceous, not dividedby a longitudinal suture, but incumbent upon each other ; as thecunex, lig. 17.
3. Lepidoptera [from *.£•?«;, a scale, and wV ;ov,] are insectshaving four wings, covered with line scales in the form of powderor meal; as in the butterllv, papilio antiopa, lig. 18.
4. Neuroftera [from veajo*, a nerve, and udego*,] have fourmembranous transparent naked wings, generally like net-work ; asin thepanorpa coa, fig. 19.
5. Hymenoptera [from a membrane, and wltjnv,] are in-sects with four membranous wings, tail furnished with a sting; asin the tenthredo, fig. 20.
6. Diftera [from L* 1 , two, and are such as have only
two wings, and poisers; as in the lly, musca, fig. 21.
7. Aptera [from a,without, and ra-h^y,] insects having no wings,This last division contains scorpions, spiders, crabs, lobsters, &c.See Aranea, Cancer, &c. To insert here the characters of allthe different genera is not necessary, as they will be found in theirorder in the course of the work.
Of the Trivial Names of the various Species of In-sects.
The trivial names of the various species of insects, subjoined tothose of their respective genera occasion little or no controversy.They are current like money, and of the same utility as the propernames of men. Insects living on vegetables should receive theirnames from the particular plants on which they mostly feed, asthat method is preferable to all others. Thus the names of the coc-cus cacti, phalama mori, &c. are excellent; and when we are ableto give such to insects, the old ones ought to be discarded! But wemust be cautions of not being too hasty in our judgement in this re-spect ; as insects, when they cannot get their favourite food, willoften eat other plants. Thus the silk-worm, for want of mulberrvleaves, will eat those of lettuce, though it will not be so wellnourished by them. Various other instances of the invention oftrivial names may be met with in the Systema Nature , particularlyamong the butterflies and moths. To prevent confusion from thegreat number of species which constitute the genus of phalama,they are distributed into sections, and distinguished by the terms ofbombyces, noctuie, geometry, tortrices, pyralides, tinea;, and alu-cit:e. The bombyces, and noctus, which are so much alike, thatthe females of the bombyces are with great difficulty distinguishedfrom the noctux, are named promiscuously. All the geometrichave their names terminating in aria and ata, according as theirantennal are setaceous or pectinated; The tortrices, in aria; thepyralides, inalis; the timne, in fella; and the alucitae, in dactyls:so that it is evident from the termination, to what section the insectis to be referred. It were to be wished that similar institutionscould be formed throughout the whole science, as here the nameitself serves to distinguish the insect.
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ENTOYER,