114 



FIRST LESSONS IN ZOOLOGY. 



number of joints as in the beetle. Like the body, they are 

 covered with fine but still' bristles. There are five toe- 

 joints, the last one with two claws. Between the claws is 

 a cushion divided into two lobes or divisions, and armed 

 with hairs, which are tubular, and secrete a sticky fluid, 

 which aids the fly in walking upside-down on glass win- 

 dows or the ceiling of a room. 



We may here relate our experience in rearing house-flies. 

 They are attracted to horse-manure, in which the young 

 live in great numbers. On placing a fly in a glass bottle, 



FIG 125. The early stages of the common house-fly. A, dorsal and side view 

 of the larva; a, air-tubes; s/>, spiracle. (.', the spiracle enlarged. F, head of 

 the same larva, enlarged; bl, labrum (?); md. mandibles; ?. . maxillse; at, an- 

 tennae. E, a terminal spiracle much enlarged. D, puparium; sp, spiracle. 

 (All the figures much enlarged.) 



she laid, between G P.M., August 12th, and 8 o'clock the 

 next morning, 120 eggs, depositing them in stacks or piles. 

 The egg is long and slender, cylindrical, and .04 to .05 of 

 an inch long and about one fourth as thick. In twenty- 

 four hours after they are laid the larva or maggot hatches, 

 and is as represented in Fig. 125, A. It is footless, a 

 smooth round white worm, with the merest rudiments of 

 mouth-parts, as seen at F. In a day it grows too big for 

 its skin, which bursts and peels off; this is again repeated 

 a day later. The maggot thus sheds its skin twice, and 



