304 



The larvae are very commonly attacked by internal bacteria and 

 other parasitic organisms, but are not, as far as I know, subject to 

 attack by insect parasites. 



HABITS OF IMAGINES 



The species occur in the neighborhood of rivers and streams, and 

 some are very persistent biters, attacking cattle, domestic fowls and 

 animals, and even man. The bite is very painful, and cases are on 

 record of the death of horses and mules as the result of their attacks. 

 There are also a few records of the death of persons from the same 

 cause. Within the past twenty years or so the species have evidently 

 grown comparatively scarce in the Mississippi Valley, being now very 

 seldom reported as injurious there. The building of levees along the 

 rivers in the middle West, with the coincident reduction in flooding 

 and the subsequent falling of the water which supplied the necessary 

 breeding conditions for these insects, has contributed largely to the 

 decrease in their numbers. 



Principal Papers on North American Simuliidae 



Barnard, W. S. 



'80. Notes on the development of a black fly (Simulium) common 

 in the rapids around Ithaca, N. Y. Am. Ent, 3:191-193. 



Forbes, S. A. 



'12. Black-flies and Buffalo-gnats (Simulium) as possible carriers 

 of pellagra in Illinois. 27th Rep. State Ent. 111., pp. 21-55. 



Garman, H. 



'12. A preliminary study of Kentucky localities in which pellagra 

 is prevalent. Bull. 159, Ky. Agr. Exper. Station. 



Hagen, H. A. 



'80. A new species of Simulium with a remarkable nymphal case. 



Proc. Bost. Soc. Nat. Hist., 20 : 305-307. 

 '83. Simulium feeding on chrysalides. Ent. Monthly Mag., 19 : 



254-255. 



Jobbins-Pomeroy, A. W. 



'16. Notes on five North American buffalo gnats of the genus Simu- 

 lium. Bull. No. 329, U. S. Dept. Agr. 



Johannsen, O. A. 



'03. Aquatic nematocerous Diptera. Bull. 68, Pt. 6, N. Y. State 

 Mus., pp. 336-388. 



