166 THE CATERPILLAR KIND. 



kind is soft to the touch, or hard, like shagreen ; the skin of the 

 latter is hairy, and as it were thorny, and generally, if handled, 

 slings like nettles. Some of them even cause this stinging pain, 

 if but approached too nearly. 



Caterpillars in general have six small black spots placed on 

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

 head. Three of these are larger than the rest, and are convex 

 and transparent : these Reaumur takes to be the eyes of the 

 caterpillar ; however most of these reptiles have very little oc- 

 casion for sight, and seem only to be directed by their feeling. 



But the parts of the caterpillar's body which most justly de- 

 mand our attention, are the stigmata, as they are called ; or 

 those holes on the side of its body, through which the animal is 

 supposed to breathe. All along this insect's body on each side, 

 these holes are easily discoverable. They are eighteen in num- 

 ber, nine on a side, rather nearer the belly than the back ; a 

 hole for every ring of which the animal's body is composed, ex- 

 cept 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 difference, that as we have but one pair 

 of lungs, the caterpillar has no less than eighteen. It requires 

 no great anatomical dexterity to discover these lungs in the 

 larger kind of caterpillars ; they appear at first view to be hol- 

 low 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 into 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 Malphigi ; 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 

 stiginata free ; and this seemed to have no effect upon the ani- 

 mal's health, but it continued to move and eat as usual : he 

 rubbed oil on the stigmata on 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 in an 

 exhausted receiver for several days together ; and though they 

 seem dead at the bottom, yet, when taken out, recover, and re- 

 sume their former vivacity. 



if the caterpillar be cut open 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 



