INSECTA—CATHKRPILLAR. 857 
it steady while the teeth are employed in cutting it; these tall upon the 
seaf, somewhat in the manner of a pair of gardener’s shears; and every 
morsel is swallowed as soon as cut. Some caterpillars feed upon leaves so 
very narrow, that they are not broader than their mouths, in this case, the 
animal is seen to devour it from the point, as we would eat a radisn. 
As there are various kinds of caterpillars, the number of their feet is 
various; some having eight, and some sixteen. Of these feet, the six fore- 
most are covered with a sort of shining gristle; and are therefore called the 
shelly legs. The hindmost feet, whatever be their number, are soft and 
flexible, and are called membranaceous. Caterpillars also, with regard to 
their external figure, are either smooth or hairy. The skin of the first 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, stings like nettles. 
Caterpillars, in general, have six small black spots placed on the circum- 
ference 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 Reau- 
mur takes to be the eyes of the caterpillar; however, most of them 
nave very little occasion for sight, and seem only to be directed by their 
feeling. 
But the parts of the caterpiliar’s body which most justly demand our atten- 
tion are the stigmata, as they are called; or those holes on the sides of its 
body, through which the animal is supposed to breathe. All along this in- 
sect’s body, on each side, these holes are easily discoverable. 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 differ- 
ence, 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 hollow 
cartilaginous tubes, and of the color of mcther-of-pearl. These tubes are 
often seen ‘to unite with each other; some are perceived to open into the 
latestines ; 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 
iastant 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 eifect 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 underwent 
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 ani- 
mals, since caterpillars will live in an exhausted receiver for several days 
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