184 PROCEEDINGS OF THE ACADEMY OF [Oct., 



without much trouble. The types of Loew, Coquillett, and others, 

 should be studied in conjunction with the few notes given below 

 in order to fix more definitely the status of some of the species of 

 those authors. To eliminate the chances of misidentification, I 

 give new names to the forms herein described, knowing full well 

 that there is a possibility of synonymy regarding some of them. 



The form of the genitalia of the male and of the seventh ventral 

 segment of the female, offers the most satisfactory characters for 

 separating several species, or, possibly, groups of species. The vena- 

 tion, with one exception, offers no usable characters, but the color 

 of the vesture may prove to be more valuable if perfectly preserved 

 specimens are available for study. In other respects, in structure 

 and color, there seems to be very little of value. The genitalia of 

 the male offers two distinct types, which may, on more detailed 

 study, show still other characters of value. The organs mentioned 

 are generally well exposed and easily seen. One type has the ''clasp- 

 ers" well developed, paired, upper and lower, finger-like. The other 

 type has no distinctly developed "claspers," but the parts corre- 

 sponding to these are developed into a polished, chitinous, half 

 disk-like organ, with a rosette of two to four thorn-like processes or 

 filaments. As mentioned above, there are probably, within these 

 two types, other characters which may prove valuable. In the 

 present study this detailed examination is not undertaken. 



Geron digitaria new species. 



cf. Black; oral margin, halteres including stalk, squamae, bases 

 of wings, pale yellowish. Tibiae brownish. Opaque. Frons, face, 

 occiput below, lateral margins of mesonotum, pleura, venter, femora, 

 gray to white pruinose. All pile silvery white, becoming slightly 

 dusky on dorsum where it is sparse. Dorsum also sparsely golden 

 lanuginous, becoming silvery below. First antennal joint black, 

 pilose. Third longer than first two together, slender, conical. Ulti- 

 mate section of fourth vein longer than preceding. Claspers of 

 hypopygium finger-like. Length, 5 mm. 



Ty-pe. — d^; Highrolls, New Mexico, June 11, 1902, (Viereck), 

 [A. N. S. P. No. 6207.] 



A series of eight males from New Jersey, Pennsylvania, Maryland, 

 Delaware, and Virginia, varying in size from 3-5 mm. are apparently 

 conspecific. The pile on the dorsum, when present, is generally 

 golden brown. A series of seven females from Pennsylvania and 

 Maryland may be associated with the above males, and are similar. 



