138 Annals Entomological Society of America [Vol. XII, 



vincing facts in support of the conclusion reached in regard to 

 completus. 



There is some doubt about Asilns dascyllus of Walker but 

 some things in the description suggests rufibarbis and the great 

 amount of collecting in Massachusetts, the type locality, up to 

 the present has not revealed any other possibilities, so have 

 used my best judgment. Walker himself transferred dascyllus 

 to Erax later when he had a better understanding of the genus. 



Van der Wulp's figure of the female of his Proctocanthus 

 virginianus is an excellent outline of Erax rufibarbis. The tip of 

 the oviduct is quite suggestive and it is not right for Procta- 

 canthus at all. The size is right and the description is not bad. 



Erax bicaudatus n. sp. 



Male. Total length 24 millimeters. Mystax and beard white, 

 palpi black with black hair. Thorax largely with white hairs and 

 bristles. Mid-dorsum before the suture with a row of rather long black 

 hairs, which is suggestive of the mane in the jubatus group, although 

 quite different, for it is made up of numerous hairs somewhat sparsely 

 placed over a rather wide strip and does not form a dense comb as in 

 the group mentioned. Well preserved specimens show it to best 

 advantage. Scutellum with black hair on the disc and numerous white 

 bristles placed irregularly on the margin. Wings hyaline, costa not 

 dilated, branching of third vein a little before the base of the second 

 posterior cell, stump of the anterior branch somewhat longer than the 

 basal section. Legs largely black with numerous white hairs and black 

 bristles, tibia reddish on basal third, especially the anterior and middle 

 pairs. Abdomen dark, partly gray pollinose with much white hair 

 and dorsally with some short black hair, segments six and seven silvery. 

 Hypopygium medium sized, black, reddish in part, clothed mostly 

 with white hair. 



Female. Total length 25 millimeters. Colored like the male and 

 differing only in sexual characters, oviduct about as long as abdominal 

 segments six and seven, viewed from side narrowed abruptly before 

 apex with a backward projecting point which from dorsal view is seen 

 to be furcate. 



Male type from Montclair, Colorado, July 30, 1898, and 

 allotype from Morrison, Colorado, May 20, 1898. Both 

 localities are near Denver. 



Numerous other specimens of both sexes from a wide 

 range, varying in size from 17 to 31 millimeters, and slightly 

 in color, some specimens appearing much blacker than others. 



The structure of the oviduct will separate the female from 

 all species of its genus except rufibarbis, of which bicaudatus 



