THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 219 



hind margin recedes to the anal angle, which is still rather prominent 

 but narrow. 



Female. — Face wide, yellowish gray; fore tarsi plain, only a little 

 longer than their tibiae, yellow, slightly darkened from tip of first 

 joint, still only blackened from the tip of third joint; wings nearly as 

 in the male, except that there is no sinus on hind margin, but they 

 recede from the tip of the sixth vein to the anal angle as in the male, 

 so as to give a flattened appearance to the anal angle. 



Redescribed from the type specimens in the American Museum, in 

 New York City; they were taken in Price County, Wisconsin. 



The following notes may help the student to separate the preceding 

 group of species, some of which might be found difficult to determine 

 with certainty: There are 10 species (lohatus, omnivagus, ampJiericus, 

 speciosus, procerus, xratus, walJceri, coloradensis, suffiavus, completus), 

 which resemble each other in having the first antennal joint yellow or 

 mostly yellow, third wholly black; in the general form of the fore 

 tarsi; in having the hind tibiae wholly yellow or nearly so, and the 

 hind tarsi wholly black. 



The first three of these have the second antennal joint yellow, at 

 least on the inner side; amphericus has only the inner side of the 

 second antennal joint yellow, it also differs from the other two in 

 having the fifth joint of fore tarsi much smaller and not so round in 

 ontline; lohatus has the apical edge of the fifth joint of fore tarsi evenly 

 rounded, while in omnivagus there is a conspicuous emargination near 

 the lower corner. In procerus and seratus the first two joints of fore 

 tarsi are of about equal length; in walkeri the second is three-fourths 

 as long as fii'st, in completus it is two-thirds as long, and in colora- 

 densis it is more than half as long as first; in speciosus and suffiavus 

 the second is distinctly less than half as long as first. In procerus the 

 third joint of the fore tarsi is a little more than half as long as the 

 second, while in seratus it is only about one-fourth as long as second; 

 completus differs from coloradensis in having the third joint less than 

 half as long as second, while in the latter it is more than half as long 

 as second. In speciosus the second joint is about equal to the third 

 in length, while in suffiavus the third is distinctly shorter than sec- 

 ond. There are other points of difference but these should make the 

 determination of these species sure. 



No. 158. DOLICHOPUS AFFLICTUS Osten Sacken. 



Hygrocelevthus afflictus Osten Sacken, Western Diptera, 1877,p.313. — Wheeler, 

 Proc. Calif. Acad. Sci., vol. 2, 1899, p. 3.— Melander and Brues, Biol. Bull., 

 vol. 1, 1900, p. 132. 



Male. — Length 5-6 mm.; of wing 5-5.8 mm. Face wide, white. 

 Front shining green. Antennae black; first joint rather long, yellow 

 on lower half; with stiff black hairs above; third joint about as long 

 as wide, pointed at tip. Lateral and inferior orbital cilia yellowish 



