ON BLACK-FLIES AND BUFFALO-GNATS 
(SIMULIUM) AS POSSIBLE CARRIERS 
OF PELLAGRA IN ILLINOIS 
By STEPHEN A. FORBES, State: Entomologist 
Purpose and Scope oe the Work 
In August, 1910, I was advised by Dr. Oliver S. Ormsby, Sec¬ 
retary of the Pellagra Commission of this state, that this Com¬ 
mission was especially interested in the distribution of our various 
species of black-flies ( Sinmlium ), because of the supposed relation 
of these insects to the introduction and spread of pellagra, and 
that it would like to have my aid in securing information upon this 
subject. In view of the fact that it is made by law one of the 
duties of the Entomologist of Illinois “to investigate all insects of 
this state injurious or dangerous to the public health,” I was very 
willing to take this subject up; and I was fortunately so situated 
as to make it possible to begin upon it at once, the one of my 
assistants, Mr. Charles A. Hart, who is best acquainted with 
aquatic insects, being stationed at the time on the .Illinois River 
at Havana for a study of the mosquitoes at that point, made in 
the hope of finding means to suppress a troublesome mosquito in¬ 
festation on the grounds of the Chautauqua Association of the 
Illinois State Epworth League. The necessary instructions were 
sent to him August 8, 1910, and he devoted a considerable part 
of the remainder of the season to a search for black-fly larvae and 
adults in and near the waters of the Illinois River and of its 
smaller tributaries, from Matanzas Lake, below Havana, to Peoria. 
As only a mere beginning could be made upon the subject 
within so short a time, and as the funds available were mainly 
already assigned to other problems, an item for the expenses of 
an investigation of this subject w 7 as included in my estimates for 
the years 1911-1912, as submitted to the Legislature at its 47th 
session, in 1911. This appropriation was not allowed, however, 
and no adequate w r ork could be done this year. I have neverthe¬ 
less brought together all published information upon the subject 
of the distribution and life histories of black-flies in Illinois, all 
