bibionidte. 39 



dilated in the male; the last joint very small. Wings large 

 and broad, with distinct alula?, anterior veins thickened, the 

 others slender ; auxiliary vein terminating in the costa about 

 the middle of the wing ; humeral cross-vein present; second 

 longitudinal vein wanting, the first and third lying close by 

 each other; the third arising from the first rectangularly be- 

 foi'e the end of the auxiliary vein ; anterior cross-vein very 

 short ; fourth vein curved, forked nearly opposite the anterior 

 cross-vein ; the forks terminating near the tip of the wing. 



The family Simuliidte, comprising about seventy-live known 

 species, is one of the best known popularly among diptera, on 

 account of the troublesome character of the flies, which are 

 scarcely less annoying than tlie true mosquito; they rarely 

 exceed five or six mm. in length, usually not more than three 

 or four, and will be immediately distinguished from the mos- 

 quito by their thick-set apjjearance, their shorter legs, their 

 shorter proboscis, and less slender antennae. In the southern 

 .States they are known as "buffalo gnats" and '-'turkey gnats", 

 and sometimes occur in almost incredible numbers ; cattle 

 when attacked by large numbers are driven almost frantic, 

 and will seek to evade them by rolling in the dust, rusliing 

 about, or going into the water. When the flies are numerous 

 they will almost literally cover the cattle, especially seeking 

 the openings of the body, entering the nostrils and the ears, 

 the margins of the eyes, where they will actually lie piled 

 upon each other. When very numerous they will produce an 

 inflanunatory fever, frequently terminating in death. The 

 well known European S])ecies is S. ro/intilxfcvense, Avhich during 

 some seasons in the regions of the Danube costs the death ot 

 many cattle. 



The larva? are very interesting crcatui'es ; tliey are acjuatic;, 

 living most frequently in mountain streams, on stems of 

 plants, or stones, where they form for themselves elongated 

 cocoons, opened a))ove. In the open end (jf these cocoons tlie 

 |)upa! ensconce themselves with the anterior ])art of the body 



