1909] Rohherflies of the Genus Asilus . 167 



Asilus arizonensis Williston (Figs. 39, 40 and 41). 



Ground color of the body dull black, posterior margin of each 

 abdominal segment plainly yellowish gray, wings uniformly fumose, 

 legs reddish. Length 1(3 to 19 millimeters. 



Gibbosity of the face small, clothed with white bristles, sometimes 

 the two uppermost bristles are black; face and front clothed with gray 

 dust. Antennae black, or in some cases partially reddish, first seg- 

 ment of each nearly twice as long as the second, third segment, 

 without the arista, a little shorter than the first two together, arista 

 about equal in length to the third segment; bristles of the rear of the 

 head light colored, although one or two on each side are often black. 

 Thorax clothed with yellowish gray dust, notum with the usual darker 

 areas; wings uniformly light smoky brown; legs reddish in general 

 color, coxae clothed with gray dust and hairs ; outer side of each femur, 

 apex of each tibia and all of each tarsus beyond the apical part of 

 each metatarsus infuscated. Abdomen dull black above, posterior 

 border of each segment with a yellowish gray band, sides and venter 

 gray. 



The type of this species is in the Francis Huntington Snow Col- 

 lection. It is a female and is labelled as coming from Arizona. Be- 

 sides I have studied a male and two females from southern Arizona 

 and fifteen males and females taken in the Huachuca Mountains of 

 Arizona by myself July 28, 1907. Most of the latter specimens were 

 taken from stones lying at the edge of a small brook where they had 

 stationed themselves to watch for insects they desired for food. 



This is the largest North American species of its group so far 

 known. The wing in the type is just a shade lighter than in the other 

 specimens. It is possible that this is due to fading for the specimen 

 appears as if it is fully developed. The species is very easy to iden- 

 tify on account of its large size and almost fumose wings. 



In a former paper published in the Ohio Naturalist, I identified 

 the next species as arizonensis, btit after studying the type it is evident 

 that that conclusion was wrong. I did not have specimens of the 

 present species when I wrote the paper referred to. 



Asilus limpidipennis n. sp. 



Gray species with hyaline wings and red legs. Body of the male 

 quite slender, legs distinctly more slender than in arizonensis. Length 

 17 millimeters. 



Gibbosity of the face very small, with a few white bristles; front 

 and face white; bristles and hairs of the head all white; first segment 

 of each antenna black, second more or less yellowish and shorter than 

 the first, third black, exclusive of the arista about as long as the other 

 two together, arista slender and slightly shorter than the third seg- 

 ment. Thorax covered with gray dust with a mid-dorsal dark stripe, 

 narrowly divided before, and two spots on each side, one before and 

 the other behind the transverse suture. These brown markings are 

 not so prominent as in some of the other species of the genus. Wings 

 hyaline, legs largely reddish, coxae colored like the thorax, femora 



