THE LIFE CYCLE 



93 



flies and moths is usually called), which hatches from the 

 egg in three or four days, is a creature bearing little or no 

 resemblance to the beautiful winged imago (the adult but- 

 terfly). It is worm-like, and instead of having three pairs 

 of legs like the butterfly it has eight pairs ; it has biting 

 jaws in its mouth with which it nips off bits of the green 

 milkweed leaves, instead of having a long, slender, sucking 

 proboscis for drinking flower nectar as the butterfly has. 

 The body of the crawl- 

 ing worm-like larva 

 (Fig. 43, b) is greenish 

 yellow in color, with 

 broad rings or bands of 

 shining black. It has 

 no wings, of course. It 

 eats voraciously, grows 

 rapidly and molts. But 

 after the molting there 

 is no appearance of 

 rudimentary wings ; it 

 is simply a larger worm- 

 like larva. It continues 

 to feed and grow, molt- 

 ing several times, until 

 after the fourth molt it 

 appears no longer as an 

 active, crawling, feed- 

 ing, worm-like larva, but as a quiescent, non-feeding pupa 

 or chrysalis (Fig. 43, c). The immature butterfly is now 

 greatly contracted, and the outer chitinous wall is very 

 thick and firm. It is bright green in color with golden dots. 

 It is fastened by one end to a leaf of the milkweed, where 

 it hangs immovable for from a few days to two weeks. 

 Finally, the chitin wall of the chrysalis splits, and there 

 issues the full-fledged, great, four-winged, red-brown butter- 

 fly (Fig. 43, d). Truly this is a metamorphosis, and a start- 



FIG. 44. Metamorphosis of mosquito (Culex). 

 a, larva ; b, pupa. 



