THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 259 



shorter; costa without an enlargement; hind margin of Aving rather 

 evenly rounded, the anal angle being rounded, still rather prominent. 



Redescribed from 3 males and several females. The males are from 

 the following places: Big Stone City, South Dakota, taken by J. M. 

 Aldrich; Franconia, New Hampshire, taken by Mrs. Slosson; I took 

 1 at Portage, New York, July 1, 1917. 



Type localities.— IWivLOVi, and West Point, New York. Melander 

 and Brues report it from Massachusetts; Johnson from New Jersey. 



Tjjyes.—ln Museum of Comparative Zoology, Cambridge, Massa- 

 chusetts. 



If we compare the six forms, palaestricus, latillifer, ddkotensis, 

 tonsv^, eudadylus and versutus, which have just been described, we 

 find them divided into two groups, one having the fore tarsi gradually 

 compressed and widened from the base of the third joint to the tip 

 of the fourth, these two joints being white; the fifth joint is much 

 compressed and wider, black; this group contains hatiUifcr Loew, 

 palaestricvs I^oew, and dal{:otensis Aldrich; in the first two of these 

 the fourth joint of fore tarsi is less than half as long as the fifth, 

 while in dakotensis the fourth is three-fourths as long as fifth; in all 

 three of these species the fifth jouit is very large and about the same 

 size and shape; these three also have the cilia of the hind femora as 

 long or scarcely as long as the width of the femora; palaestricus is 

 separated from hatiUifer by the color of the posterior tarsi, which are 

 black nearly or quite to their base in palaestricus; still sometimes the 

 first joint is largely yellowish, but the yellow shading into the black 

 is not sharply defined, while in hatiUifer the first joint is yellow with 

 the tip sharply black, or rarely almost wholly yellow; in hatiUifer the 

 cilia of hind femora are dense and occupy the center of the femora, 

 while in palaestricus they are more scattering and extend nearly to 

 their tips; the glabrous surface on inner side of hind tibiae in this 

 form extends about two-thirds of their length, while in hatiUifer it 

 reaches only about half their length; the third and fourth joints of 

 fore tarsi are not so wide in hatiUifer as in palaestricus. The other 

 three forms have the third joint normal, the fourth joint much 

 compressed and wide, and it is white, the fifth joint still more ex- 

 panded and black; tonsus has the lower surface of the hind femora 

 vathout cilia, while in the other two it has long yellow cilia; this 

 form also has the fourth and fifth joints of fore tarsi of nearly equal 

 length; eudadylus and versutus are separated, fu-st, by the ciHa of 

 the hind femora, which are longer than the w4dth of the femora in 

 versutus and scarcely as long as the width of the femora in eudadylus; 

 second by eudactylus having the third and fourth joints of fore tarsi of 

 nearly equal length and the fifth joint distinctly shorter, while in 

 versutus the third and fifth are nearly equal in length and the fourth 

 is distinctly shorter than either of these. 



