252 



DIPTERA. OR TRUE FLIES. 



a family that contains the Blue-bottle Flies (Cal/ii'hora) and 

 Green-hottle Flies {Lucilia), as well as the dreaded Tsetse-flies ■ 

 of Africa {Glossiruv). 



This household pest is found in all parts of the world near 

 habitations. The adult house-fly is ashy-grey, more or less 

 ochreous at the sides in the male, ashy-grey in the female; 

 head black between the dull-reddish eyes, which are surrounded 



?;.o. 



Fig. 144. — TnK Hch'se Fly Qftisca domestica). 



.■ , Mandible of larva b ; 



, anterior spiracles of larva ; d, eggs ; f, puparium ; 

 /, spiracnlar remnants. 



by a shiny white circle, and the face is the same colour ; the 

 grey thorax has four black lines upon it, and the legs are rather 

 slender and black. The life-history of this species may briefly 

 be summed up as follows : Tlie Hies lay their eggs in putrid 

 and decaying substances, human fax-es, spent hops, iSrc, but 

 especially in horse-manure ; they deposit their eggs in batches, 

 each fly producing from one hundred to one hundred and fifty 



