196 



ELEMENTAEY STUDIES IN INSECT LIFE 



FIG. 171. 

 bids) and 



A fly (Sarcophaga cim- 

 its pupa-case, showing 



DIPTERA. 



Insects with haustellate mouth-parts, front wings 

 membranous, hind wings replaced by knobbed processes 

 called halteres. The- metamorphosis is complete. 



The name is derived from 

 5 dis, double, and Trrepdv, 

 pteron, wing. The Diptera 

 include all insects which 

 can properly be called flies. 

 Such forms as the house-fly, 

 the mosquito, and the horse- 

 fly are Diptera. While the 

 mouth is fitted for sucking, 

 in some flies such as mos- 

 quitoes that organ is fitted 

 for piercing the skin and 

 sucking the blood. The or- 

 der is a large one, and the species differ much in man- 

 ner of life. The larvae are commonly called maggots. 

 The females generally lay their eggs in the vicinity 

 of the proper food for the maggot. Our common house- 

 fly prefers fresh horse-manure for oviposition. Upon 

 this the maggot feeds about a week, then transforms 

 into the pupal stage, remains so for about another week, 

 and then comes forth as a two-winged insect to find its 

 way inside mosquito-barred doors and windows, or into 

 dwelling-houses not properly guarded. 



The method of emergence from the pupal case is -of 

 interest. The larvae of more generalized forms such as 

 the robber-fly, come forth from a straight seam in the 

 side of the case, and in this differ not at all from the 

 mode of many other insects. In the case of the more 



bursting off of end of pupa-case to be 

 its method of emerging. Enlarged. 



