478 



OTHER BLOOD-SUCKING FLIES 



Blackflies or Buffalo Gnats 



General Account. The blackflies, as annoyers of domestic 

 animals and man, are among the most important of insect pests. 



The females are most insatiable blood- 

 suckers, and have been known to at- 

 tack cattle in such swarms as to kill 

 them; a Himalayan species, accord- 

 ing to Alcock, has been said to kill 

 even human beings in the same way. 

 These small insects, which constitute 

 the family Simuliidse, are quite unlike 

 the other flies of the group to which 

 they belong. Instead of the usual 

 slender, long-legged, midgelike flies of 

 this group we have in the blackflies 

 small, robust, humpbacked creatures 

 with short legs and broad wings, rather 

 FIG. 219. Biackfly SimuUum resembling, in a general way, minia- 



pecuarum. X 7. (After Riley.) J ' 



ture houseflies (Fig. 219). The an- 



tennae are composed of 11 segments, but they are short and 

 stocky, and have no hairs at the 

 joints. The proboscis in the 

 female is short but heavy and 

 powerful, while in the male it 

 is poorly developed. The mouth- 

 parts are made up of the same 

 parts as in mosquitoes, but are 

 dagger-like instead of needle- 

 like (see Fig. 220). Most of the 

 northern species are black in 

 color, whence their name, but 



, Al FIG. 220. Mouthparts of blackfly, 



SOme Ot the Species are red- SimuUum; ant., antenna; ep., epiphar- 



dish brown Or yellowish, and > rnx ; ^P- hypopharynx; lab., labium; 



,, . label., labellum; mand., mandible; 



they may be Variously Striped max., maxilla; max. p., maxillary pal- 



and marked. The wings are pus - (After Alcock.) 

 either clear or of a grayish or yellowish color with the few 

 heavy veins near the anterior margin often distinctively 

 colored. Some of the species are not over one mm. (-$ of 



--ant, 



\ctbel 



