THE CATERPILLAR. 



493 



fore ring, and a little to the side of the head 

 Three of these are larger than the rest, anc 

 are convex and transparent : these Reaumu 

 takes to be the eyes of the caterpillar ; how- 

 ever most of these reptiles have very little oc 

 casion for sight, and seem only to be directec 

 by their feeling. 



But the parts of the caterpillar's body which 

 most justly demand our attention, are the stig 

 mata,as they are called ; or those holes on the 

 sides of its body, through which the animal is 

 supposed to breathe. All along this insect's 

 body, on each side, these holes are easily dis 

 coverable. They are eighteen in number 

 nine on a side, rather nearer the belly than 

 the back; a hole for every ring, of which the 

 animal's body is composed, except the second 

 the third, and the last. These oval openings 

 may be considered as so many mouths, through 

 which the insect breathes ; but with this dif- 

 ference, that as we have but one pair of lungs 

 the caterpillar has no less than eighteen. I 

 requires no great anatomical dexterity to dis- 

 cover these lungs in the larger kind of cater- 

 pillars : they appear, at first view, to be hollow 

 cartilaginous tubes, and of the colour of mother- 

 of-pearl. These tubes are often seen to unite 

 with each other ; some are perceived to open int 

 the intestines ; and some go to different parts of 

 the surface of the body. That these vessels 

 serve to convey the air, appears evidently, from 

 the famous experiment of Malpighi ; who, by 

 stopping up the mouths of the stigmata with 

 oil, quickly suffocated the animal, which was 

 seen to die convulsed the instant after. In 

 order to ascertain his theory, he rubbed oil 

 upon other parts of the insect's body, leaving 

 the stigmata free ; and this seemed to have no 

 effect upon the animal's health, but it continued 

 to move and eat as usual : he rubbed oil on 

 the stigmata of one side, and the animal under- 

 went a partial convulsion, but recovered soon 

 after. However, it ought to be observed, that 

 air is not so necessary to these as to the nobler 

 ranks of animals, since caterpillars will live 

 iti an exhausted receiver for several days to- 

 gether ; and though they seem dead at the 

 bottom, yet when taken out, recover, and re- 

 sume their former vivacity. 



If the caterpillar be cut upon longitudinally 

 along the back, its intestines will be perceived 

 running directly in a straight line from the 

 mouth to the anus. They resemble a number 

 of small bags opening into each other ; and 

 strengthened on both sides by a fleshy cord by 

 which they are united. These insects are, 

 upon many occasions, seen to cast forth the 

 internal coat of their intestines with their food, 

 in the changes which they so frequently undergo. 



But the intestines take up but a small part 

 of the animal's body, if compared to the fatty 

 substance in which they are involved. This j 



substance changes its colour when the insect's 

 metamorphosis begins to approach ; and from 

 white it is usually seen to become yellow. If 

 to these parts we add the caterpillar's imple- 

 ments for spinning, (for all caterpillars spin at 

 one time or another,) we shall have a rude 

 sketch of this animal's conformation : how- 

 ever, we shall reserve the description of those 

 parts till we come to the history of the silk- 

 worm, where the manner in which these in- 

 sects spin their webs, will most properly find 

 a place. 



The life of a caterpillar seems one contin- 

 ued succession of changes, and it is seen to 

 throw off one skin only to assume another ; 

 which also is divested in its turn : and thus 

 for eight or ten times successively. 1 We 

 must not, however, confound this changing ot 

 the skin with the great metamorphosis which 



1 One of the most singular circumstances respecting 

 the moult of caterpillars, is the manner in which the 

 hairs are deposited in the new skin before moulting. 

 These are not, like the feet and other organs, sheathed 



Moulting of caterpillars, a a, caterpillar magnified, l> b, the 

 same when it has just cast its skin, the hairs still moist; r, the 

 same, natural size; d efg. tufts of its hairs magnified; //, leg ami 

 "oot magnified; , the caterpillar wedging through the old skin ; 

 *, hairy caterpillar of the sycamore. 



in the hairs of the old skin, hut smoothly folded down 

 iu separate tufts ; and if the old skin be removed a short 



