FIELD BOOK OF INSECTS. 



19. Posterior acrosticals feebly developed; thorax some- 

 what flattened between the suture and the scutellum; 

 usually bluish-black; squamae brownish 



Protophormia terrce-novce. 



Posterior acrosticals moderately developed; thorax 

 not flattened; dark greenish or bluish; squamae whitish. 



Phormia regina. 



20. Having two posterior acrosticals; greenish or 

 bluish Lucilia ccesar . 



Having three posterior acrosticals; greenish or 

 bronzy, rarely bluish Lucilia serricata. 



Haematobia 



Plate LXIX. The name Texas Fly was 



based on the supposition that this species 

 irritans . . . _,_ 



originated in the West. It came from 



Europe to the vicinity of Philadelphia about 1887 and is 

 now found from Canada to the Gulf and at least as far 

 west as Idaho. It was formerly abundant in the East but 

 is now quite rare. The name Horn-fly comes from the 

 habit w r hich the adults have of clustering about the base 

 of the horns of cattle to suck blood. The larvae live in 

 cow dung. 



The figure (Plate LXX) and the piercing 



Stomoxys mouth parts of the Biting House-fly make 



calcitrans . , ._ . 



identification easy. Hough says that speci- 

 mens taken on the borders of woods often have brownish 

 wings. Their superficial resemblance to M. domestica 

 and their biting habits have given rise to the error that the 

 latter species is adding to its many sins by sucking blood. 

 Both sexes suck blood. On account of calcitrans being 

 more troublesome during rains, it is sometimes called 

 the Storm-fly. Another common name is Stable-fly. 

 It has recently been accused of carrying infantile pa- 

 ralysis. The larvae feed on a wide range of decaying 

 matter, including fermenting grass cut from lawns, 

 horse manure, and human excrement. It is world-wide 

 in its distribution. 



268 



