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THE BUFFALO-GNATS, OR BLACK-FLIES, OF THE UNITED STATES. 
[A 8\uoiiHi8of Iho tljptcrouM family Shuuliida.'.] 
lij' 1). W. CociUILLE'lT. 
The dipterous family Siiiiuliida» eoutains but the single genus 
Simulium, of which the black-tiy of the North and the buffalo-gnat of 
the South are well known exaini)les. They outrival the nioS(iuito in 
their bloodthirsty projiensities, poultry and even domestic animals 
sometimes losing their lives from their attacks. 
The black-Hy of the North is the tSimuliinn rcnusttnn Say, of which 
tS. molrstum Harris and S. phciiidium JJiley are synonyms. It is not 
contined to the North, however, but ranges southward as far as Bis- 
cayne Bay, Florida, and is found in the other Southern States, extend- 
ing westward to California. The larvie of this si)ecies were formerly 
supi)0sed to cause the death of young trout, but this accusation has 
since been disproved. 
The life history and habits of two other species, the Southern buffalo- 
gnat and the turkey-gnat, have been very thoroughly investigated by 
this Division, and a full account was published in the annual report of 
this Department for the year 1880. Neither of these species is con- 
fined to the South, both ranging as far northward as New Hamp- 
shire and Massachusetts. The food of the larvie consists chietly of 
microscopic Crustacea. 
In their relations with man, the most annoying species are *S'. venus- 
tum^ the black-fly of the north woods, and aS. invenustiDn. the buff'alo- 
guat of the South. There is at least one authentic record of the death 
of a human being through the attacks of the latter species. Dr. How- 
ard has called attention to the fact that although ^S'. invcuustum breeds 
abundantly in Ilock Creek, near Washington, D. C, it is not known to 
bite human beings in this vicinity. ^loreover, he informs me that the 
same species, in May and the early part of June in wet seasons, occurs 
abundantly in portions of the Catskill Mountains, and that, although it 
is very annoying by tlying about the face and crawling over the skin, 
it rarely bites. Dr. Howard has also studied the habits of ^S.2fictipes 
at Ithaca, N. Y., and has recorded some observations on the larvae and 
egg laying (the latter having been made by Professor Comstock) of this 
species in Insect Life, Volume 1, pages 1)1)-101. He says that this species 
also, although its larvie occur in enormous numbeis in the swift-ruuuiug 
rock streams about Ithaca, does not. in the adult stage, seem to bite 
human beintrs.' 
'The raost complete series of observations Avbich luas been uv.uh- ujion any species 
of Siinuliuni, aside from those reconled in the annual rep(»rt of this Departinent for 
18Sfi, upon the butfalo-jjjnat of the southwest, was made «luriu«:: ISSO-IK) by Miss 
K. ( ). Phillips, a student in the laboratory of Prof. .T. H. Comstock, at Cornell Uni- 
versity. The results of Miss Phillips's obsiivations were embodied in her «;raduat- 
in^ thesis, which has never l)cen ])ublished. I'lolessor Comstock has ])ermitted the 
writer to examine the thesis and to extract the followiui; faets : 
The species stmlied was Simulium picti^ies llageu. The adult occurs near Ithaca in 
