166 MEDICAL ENTOMOLOGY 



lobelia. Thorax gently arched, and without a transverse suture ; scutell- 

 um small. Abdomen cylindrical, broad, slightly ovoid and sometimes 

 tabanid-like, consisting of eight segments, the first being the longest ; 

 external genitalia of male concealed. Legs well developed, never very long, 

 femur broad and flat ; tibia usually with a terminal spur ; metatarsus 

 much longer than the succeeding tarsal segments ; the last joint is small ; 

 empodium rudimentary. The metatarsus is as a rule broadly swollen 

 in the male. Wings large and broad, anterior veins thickened and 

 spinulose, the remainder poorly developed and often almost invisible. 

 The subcostal or auxiliary vein ends about the middle of the costa ; 

 the second long vein is wanting ; the third arises from the first at its 

 middle, and is forked ; the fourth is a little curved, and is forked close 

 to the base of the wing. 



This family contains the single genus Simulium, Latrielle. Alto- 

 gether there are about one hundred species, distributed all over the 

 world. Roubaud (1906) suggested splitting the genus into two sub- 

 genera as follows : Eii-Simulium, in which the second hind tarsal 

 joint is short in both sexes, is curved, and has a dorsal notch at the 

 base. The pupa has a small number of respiratory filaments, an 

 incomplete cocoon, and is solitary. Pro-Simulium, in which the 

 second hind tarsal segment is elongated, straight, and has no notch 

 at the base. The pupa has a large number of respiratory filaments, 

 a complete cocoon, and is found in company with others. 



The Simuliidae are well known in most parts of the world on account 

 of the great annoyance, and at times serious damage, which they may 

 cause. In Europe and in India they are frequently called ' sand flies,' 

 a name better reserved for the species of the genus Phlebotomies. In 

 America they are known as ' buffalo gnats,' or ' turkey gnats,' the latter 

 from the fact that they readily attack these birds and other fowls. 

 Both in America and in the 'southern parts of Hungary these flies are 

 often the cause of serious loss to farmers and stock breeders. They 

 appear in swarms, attacking domestic animals of all kinds, and so irritate 

 them by their bites that they manifest the most violent signs of fear 

 and distress, shaking themselves, lashing their tails, and even careering 

 wildly about in their efforts to rid themselves of their tormentors. 

 Cattle will at times immerse themselves completely in water in search 

 of relief. Birds are not exempt from their attacks, as their American 

 name implies, and are often so tormented that they are driven from 

 their nests. The flies bite them about the head and eyes, but will also 



