INSECTS, 



127 



FIG. 157. Tongue of blow-fly. 



(Fig. 156) about fourteen days. 

 The proboscis of the fly (Fig. 

 157) is a fleshy, tongue-like 

 organ bent under the head 

 when at rest. In flying, the 

 wings describe a figure 8 in 

 the air, making 19,800 revolu- 

 tions in a minute, or 9,400 

 simple oscillations. The eyes 

 (Fig. 158) are both compound 

 and simple. The feet (Fig. 

 in) have delicate pads for 

 clinging upon smooth surfaces. 

 Fleas (PuKcida) . The 

 fleas (Fig. 160) are wingless, 

 have a compressed body, and 



FIG. 158. Showing 

 . compound and sim- 

 ple eyes of fly. 

 A, head, enlarged 

 8 times : c, com- 

 pound eye ; j, sim- 

 ple eyes. B, por- 

 tion of the surface 

 of a compound eye, 

 highly magnified. 



FIG. 159. Spiracle of a fly. 



