AMl'RICAN BLACK VUES OR BUFFALO GXATS. 



INTRODUCTION. 



Both in Europe and in America some of the species of the family 

 Simuliithe have for years been regarded as being among the worst of 

 insect pests, and in some cases as a menace to the lives of cattle and 

 even of human beings. The common species, Slmnliuin cohnmibacz- 

 ense Schonbauer, of southern Europe, has the reputation of being 

 very destructi^■e and, if credence be given to ivcords, it certainly 

 equals the evil i-cputation of any other bloodsucking species in so 

 far as the eirects of its attacks on cattle are concerned. Lately there 

 has been a suggestion made that some species of this group may 

 be the transmitter of pellagra, and it is to ascertain how manj^ 

 American species occur (in so far as our material permits) and their 

 range that this work has been undertaken. That there are more 

 species llian aie listed or described in this paper there can be no 

 doubt, but in view of the fact that the early stages of the species 

 are passed in streams, from which it is not easy to remove them 

 and successfully rear them under artificial conditions, a number of 

 closeh' allied species have not been so far linked up in the adult, 

 pupal, and larval stages. It is essential to the existence of the larvae 

 that they shall remain in w^ater in which there is a current, and 

 removal to water in a jar or vessel generally kills them after a few 

 hours. The material available for study for the purposes of this 

 paper consists of the collection in the U. S. National Museum and 

 a few specimens kindh^ loaned by Prof. O. A. Johannsen and ]Mr. 

 C. W. Johnson. Much of the material in the National iMuseum was 

 collected by ]\Iessrs. A. H. Jennings and W. V. King in connection 

 with the pellagra investigations in North Carolina and South 

 Carolina in 1912. 



It is not considered necessary to rewrite the history of the 

 Simuliida? in this paper, but a bibliography is given on page 69 

 of the principal papers on the American species in the group, which 

 may be consulted with reference to the biology of the species. 



CHARACTERS OF THE GROUP. 

 EGGS. 



The eggs are deposited in many cases on blades of grass, twigs, or 

 leaves of trees which are dipping in running water. According to 



