3o8 The Ohio Naturalist. [Vol. XI, No. 6, 



directed outward in some specimens. Hypopygium rather larc:^e 

 with an extension at the apex and clothed with rather long yellow 

 hairs among which are some black ones. 



Female abdomen nearly uniform yellowish pollinose with pale 

 hairs, ovipositor about five millimeters in length, equivalent to the 

 last three abdominal segments. Several specimens from Colorado 

 and New Mexico. 



Erax dubius Williston. Gray all over, femora black, tibiae and 

 tarsi red, the latter somewhat darker than the foniier, tibiae with 

 apices somewhat darkened. Total length of the male, 21 mil- 

 limeters. 



]\l3^stax and beard white, ocellar bristles rather large and 

 black, occipito-orbital bristles mostly black, otherwise the hairs 

 and bristles of the rear of the head are white, palpi black and 

 clothed with white hairs; legs with black bristles and white hairs, 

 on the tibiae this white hair is long and conspicuous, but on the 

 femora it is in large part short and recumbent ; wings hyaline, very 

 slightly darkened at extreme apex; thorax gray pollinose, most of 

 the hairs and bristles of the dorsum black, of the sides white, 

 scutellum with white hair, and black bristles on the margin. 



First four abdominal segments with long white hairs which on 

 two, three and four are parted at the middle and directed outward, 

 fifth and following segnnents white and w4th very short white 

 hairs. Hypopygivim from above narrower than the last abdominal 

 segment, black, with hairs mostly white, apex truncate except that 

 the upper part of each valve is extended backward and inward 

 toward its fellow of the opposite side thus producing a prominence 

 from lateral view. 



I take this to be the species to which Williston gave the name 

 dubius in the Transactions of the American Entomological Society 

 XII, page 64. No description of the species appears to have been 

 written but the name is inserted in the key and enough characters 

 pointed out to make identification reasonably certain. There are 

 two males before me from southern Arizona. 



Erax argentifrons n. sp. Much like ra]:)ax. Front white pol- 

 linose, mystax white, legs with white hair. Length IS to 23 

 millimeters. 



Palpi black with white hair, occipito-orbital and ocellar 

 bristles black, antennae black, first two segments with white hair, 

 beard white. Thorax yellowish-brown with the usual middorsal 

 stripe darker, hairs of the sides almost unifonnly pale, of dorsum 

 variable between pale yellowish and black; wings hyaline, legs 

 black, except the extreme bases of the tibiae which are reddish- 

 yellow, clothed with white hairs and black bristles. 



First two segments of the male abdomen colored like the 

 thorax, segments three to seven inclusive silver white, apex of 

 two, all of three and four with long white hair parted at the mid- 



