312 



The genus was originally poorly defined, and the type species has 

 been recognized by no one since Zetterstedt's time. It is probably the 

 best course to accept as characters of this genus the very distinctly 

 haired wings and the short basal joint of the hind tarsus, as given in 

 the generic key herewith. In taking this course there is little reason to 

 anticipate objections to it, for previous authors have already adopted 

 it despite the uncertainty that exists regarding the identity of the type 

 of the genus. Kieffer, in "Genera Insectorum",* gives a list of seven- 

 teen species belonging to Forcipomyia, but strangely leaves out the 

 type species, placing it among the doubtful species in ihe genus Ccrato- 

 pogon and ciuestioning if it may not be identical with albipcnnis Mei- 

 gen, which, also, he doubtfully places in Ccratopogon. It may be of 

 interest to call attention to Kieffer's inclusion of Coquillett's species 

 pergandci and spcciilaris in Ceratopogon without any question as to 

 the correctness of this course, although both are obviously of the genus 

 Forcipomyia according to the original description. 



That the species included in the present concept of this genus are 

 entitled to rank generically distinct from those included in Ceratopogon 

 in this paper there can not be the slightest doubt, but whether the facts 

 here adduced will hold good for all the species either in North Amer- 

 ica or any other f aunal area remains to be seen. 



It has been impossible for me to include all the North American 

 species in my key, not because I am dealing only with those that occur 

 in Illinois, but because many of the species have been so imperfectly 

 described — often without reference to previously described forms, and 

 also, at times, from one sex only — that it is not possible for any one to 

 decide, without reference to the type specimens, how many species are 

 really represented by the forms described. It requires very careful 

 work and examination of slide preparations under a high-power lens, 

 to definitely decide as to the identity of most of the species. Fortu- 

 nately, realizing this early in the progress of my work, I made an ef- 

 fort to obtain a large supply of fresh material, and, having hundreds of 

 specimens, hope I have succeeded in defining the species before me in 

 such a manner that they will be recognizable by future students. 



Key to Illinois Species 



1. Females 2 



— Males 8 



2. Tibiffi, at least mid and hind pairs, with lanceolate scales in addition 



to the long slender hairs 3 



— Tibiae with only long slender surface hairs 4 



*Fasc. 42, p. 52. 1906. 



