CHAPTER XVIII. 



THE HOUSE FLY AND OTHER TWO WINGED INSECTS. 



THE "body of the fly differs in a good many points from 

 that of a grasshopper or beetle. In the first place, there 

 are but two wings ; hence the flies are called two- winged or 

 Diptera, from two Greek words signifying two wings. 



Now, closely inspecting the house-fly, we see that the 

 head is distinct from the thorax, and the latter from the 

 hind body. The three divisions are seen to be very well 

 marked. 



Turning to the head (Fig. 116) we see that the com- 

 pound eyes are very large and full. The antennae are short 



B 



FIG. 116. A. front, and B, side, view 

 of head of house-fly, oc, sim- 

 ple, e, compound, eye; nut. an- 

 tenna; mxp, maxillary palpi; {, 

 tongue; lab, labelluru. (.Magni- 

 fied.) 



tlUCf 



FIG. 117 Head and mouth parts of 

 mosquito, e, eye; , antennae; ll; 

 labrum: h, hypopharynx; in, man- 

 dibles; mr, maxillae; wj-;>, maxil- 

 lary palpus; 76, labium; c, clype- 

 us. (Magnified.) 



and two-jointed, and at rest fall down into a cavity in the 

 face ; they bear at their base two feathery bristles. 



Instead of jaws and well-formed accessory jaws and an 

 under-lip like those of the mosquito (Fig. 117), these parts 

 are transformed into a sort of tongue for lapping liquid 

 food (Fig. 118). The under-lip is changed into a great 

 fleshy proboscis (Fig. 118 A, B}, which is bent under the 



