420 



Marvels of Insect Life* 



imperfect eyes, or " ocelli." From the character of the optic structures beneath 

 them it is considered that the visual powers of the caterpillar are very poor. Its 

 principal sense organs appear to be the very small antennae, which may be found 

 one just outside each of the cutting mandibles. Tlie spinning organ, through 

 which it produces the silk threads by which it suspends itself before changing to 

 the chrysalis, will be detected as a projection from the lower lip. The spiracles, 

 or breathing pores, will be found to the number of nine along each side — one on the 

 first segment behind the head, and one on each of the segments four to eleven. 

 The greater part of the caterpillar's interior is taken up by the enormous 

 organs. The slender tubular heart runs along the 

 and the nervous system along the floor of the body, 

 rudiments of the 



stomach and digestive 

 middle line of the back, 

 There are also, however. 



future wings, which may be seen bv 

 dissection of a full-grown 

 caterpillar. These are just 

 beneath the second and 

 third segments of the body, 

 and perhaps explain \\hy 

 these two segments are 

 without spiracles. \Mien 

 about to become a chrysalis, 

 the caterpillar in most cases 

 spins a pad of silk to which 

 the chrysalis can fix itself by 

 hooks at the tail end ; it 

 also in many cases spins a 

 girdle of silk across the 

 middle of the body, the two 

 ends being securely fastened 

 to the material upon which 

 the chrysalis is to be 

 suspended. 



Having so secured it- 

 self, and thrown off the last 

 of its caterpillar-skins, the 

 chrysalis is revealed. The wings, the long legs, the antennae, the large compound 

 eyes, the long trunk, are all to be seen laid along the under side, but covered by a 

 hard skin, which is formed by the pouring out of a fluid when the caterpillar-skin 

 is thrown off. This hardens by exposure to the air, and glues down all the appen- 

 dages, forming a thin shell external to them. Now, although these organs are 

 formed in a sense at this stage, they are not properly developed ; they are, so to 

 speak, merely sketched in, and the mass of the body contents is in the condition of 

 a creamy fluid due to the breakdown of much of the caterpillar's internal organiza- 

 tion. The butterfly, subsisting upon a little liquid food, manifestly does not require 

 the enormous digestive apparatus of the caterpillar, that had to extract its nourish- 

 ment from leaves. The caterpillar was a creature of no sex — though some 



Pholo by] 



How A Caterpillar Clings. 



[Lumsden. 



The true legs of the caterpillar just behind the head are used chiefly for manipulating 

 its food. The thick, soft legs near the middle of its length are of a temporary character 

 and do not reappear in later stages of its existence. One of these pro-legs, as they are 

 called, is shown nmch enlarged to reveal the fringe of hooks which enable it to take hold 

 so readily and tenaciously. 



