CHAPTER IV 



THE FLY AND ITS ALLIES 



THE term "fly" is applied to many of the insects belong- 

 ing to the Diptera 1 or group of two- winged insects. 2 It is 

 strictly applied to the family Muscidse. 3 The most gener- 

 ally known representatives of this family are the house-fly 

 with a sucking mouth, the stable-fly with a mouth fitted for 

 piercing skin and sucking blood, and the blow-fly with a 

 steel-blue abdomen. These flies love sunshine and dry ness. 

 On a bright day they fly actively in the open air. On 

 damp days, on the other hand, they swarm into houses and 



1 5/s, twice ; irrepbv, wing. 



2 The following is a key to the principal suborders of the Diptera : 



ai. All three thoracic segments fused, usually winged ; 



under lip unsegmented. 

 61. Adults not parasitic ; maxilla; covered by upper 



lip. 

 d. Antennae long, many-jointed . . . Ncmatocera 



(Gnats and Midgets; 

 c 2 . Antenme short, usually 3-jointed ; the third 



joint ringed Bracliycera 



(Flies) 

 6 2 - Adults parasitic ; upper lip enveloped by max- 



illse as by a sheath Pupipara 



(Ex. Sheep-tick) 

 2 . The three thoracic segments separate, no wings, 



under lip segmented . . Aphaniptera 



(Fleas) 



3 musca, fly. 



62 



