6 BULLETIlsr 116, UNITED STATES NATIONAL MUSEUM. 



notably enlarged fore or middle tarsi, but the enlargement, besides 

 being purely a male character, is of every degree down to nothing, 

 and in several cases two species can be selected which differ only in 

 very minute characters or none, except that the male of one has en- 

 larged fore tarsi and the other has them plain. Rondani proposed 

 Haglieneura for a species with the bend of fourth vein angulated, a 

 very unstable character. Frey in a paper on the P^uropean species 

 cited below proposes to divide the genus into four subgenera, as 

 follows: 



All femora yellow: 



Infraorbital cilia black DoHchopus s. str. 



Infraorbital cilia whitish Eudolichopus Frey. 

 Femora more or less black: 



Infraorbital cilia whitish Leucodolichopus Frey. 



Infraorbital cilia black Melanodolichopus Frey. 



He offers these divisions for convenience in grouping the numerous 

 species, conceding that the characters used have slight morpho- 

 logical value. For our fauna, however, the division on the color of 

 the femora is worthless, as we have several types of partial infusca- 

 tion of these members; the tips of the hind femora may be infus'cated, 

 the bases of the front ones only, etc. We have also several species 

 (crenatus, etc.) in which the infraorbital cilia are pale in the males, 

 but black in the females. While these characters are used in our 

 tables, they are not generic in any degree. In fact, the more species 

 we know the more homogeneous this remarkable group appears. The 

 specific characters are beautifully distinct in most cases, but mostly 

 sexual. This species are very easy to identify from males and no 

 advantage could result from drawing lines where nature apparently 

 has drawn none. 



The present paper is the consummation of work in which I have 

 been interested for 80 years. During the winter of 18S9-90, when a 

 student in Professor Cook's laboratory in the Michigan Agricultural 

 College, I decided to take up the Diptera as a specialty. As a begin- 

 ning I tried my hand with the old Smithsonian monographs of Loew 

 and Osten Sacken, and found that I got along best with the one on the 

 Dolichopodiae, by the aid of which I could determine a fair number 

 of species, especially in Drlichpus. This roused my interest in the 

 group, and I began to collect in it actively; so that, when I went to 

 Kansas to stud}'- in January, 1893, I took along a considerable named 

 collection and some undescribed species in this genus. Combining 

 this with the University of Kansas collection, I prepared a revision 

 which included 22 new species. In the autumn of 1893 I went to 

 Idaho, and during my residence there of 20 years I had opportunities 

 to collect these beautiful insects in many parts of the West. Thus 

 I accumulated so many species that another revision became desir- 



