BIBIONID^. 



391 



wanting, while the posterior tibiae, and first joint of the hind 

 tarsi are dilated. The body is short and thick. The labrum 

 is free, sharp as a dagger, and the proboscis is well 

 developed and draws blood profusely. Tlie species 

 are numerous. The Biack-fl^', so well known as 

 the torment of travellers in the North, is black, 

 with a broad silvery ring on 

 the legs. We have received a 

 large species from Mr. E. T. 

 Cox, called in the West the 

 Buffalo fl}^ On the prairies 

 of Illinois it has been known 

 to plague horses to death by 

 its bite. The S. (Rhagio) 

 CoTumbaschense Fabr. in Hungary abounds in im- 

 mense numbers, often killing cattle. Other species 

 abound in the American tropics where they are a 

 great scourge. The cylindrical larva of the Euro- ^'S- 312, a. 

 pean species is furnished with short antennae and two flabelli- 

 form appendages. On the under side of the prothorax is a 

 thick conical and retractile tubercle, and there are several 

 curved filaments at the end of the body. The pupa has eio-ht 

 very long lateral filaments on the front of the thorax, and the 

 posterior end of the body is enclosed in a semioval membra- 

 nous cocoon, open in front, and posteriorly attached to some 

 plant. The fly leaves the pupa beneath the water. 



BiBiONiD^ Macquart. This group is characterized by hav- 

 ing three ocelli and the prothorax much developed ; the wings 

 have no discal cell. The coxje are not prolonged and the em- 

 podium (supplementary cushion) is proportionally long, while 

 the pulvilli are sometimes wanting. The typical genus, Bihio 

 of Geoflro}^, has short, nine-jointed antenna?, five-jointed palpi, 

 and the eyes of the male are large and contiguous, while tliose 

 of the females are small. The larvae are cylindrical, footless, 

 with ten spiracles, and furnished with transverse rows of short 

 hairs, being found in dung, but they mostly feed on the roots 

 of grass, whole patches of which appearing as if winter-killed. 

 Robins destroy immense numbers of them. Westwood has 



