282 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



Face very short, in the profile nearly straight, moderately advancing 

 in front of the eyes ; oral edge cut obliquely ; cheeks moderately broad. 



Froboscis, if bent backward, would reach the scutellum, linear, 

 straight, x)ointing forward; the two narrow lips at the end a little 

 curled up. In my specimen, the head is somewhat distorted from its 

 natural position ; the proboscis is longitudinally cleft in two parts, both 

 long and linear, at an angle to each other. Macquart (Dipt. Exot., 4e 

 suppL, tab, iv, f. 1) represents the proboscis of Mitrodetus [Cephalocera] 

 dentitarsis in a somewhat similar manner. ^Nevertheless, owing to the 

 imperfect condition of my specimen, I am not prepared to affirm that 

 this is a permanent character. 



Venation of the wings : — Three cells intervene between the second sub- 

 marginal cell and the margin of the wing. That cell is petiolate at the 

 proximal end, coarctate at its distal end, which coincides with the tip 

 of the first vein. The first posterior cell comes in contact with the first 

 basal cell (I mean to say, is not petiolate). The small cross-vein near the 

 posterior margin is absent, although a rudiment of it, in the shape of a 

 minute stump of a vein, is perceptible in the usual place. (The venation 

 is not unlike that in Glerstaecker, 1. c, tab. i, f. 1 ; but the second sub- 

 marginal cell is more ventricose, the contact between the first posterior 

 and first basal is broader, so that the angle of the latter is not project- 

 ing ; the discal-cell is shorter and broader, the second basal longer, the 

 small cross-vein on the posterior margin absent, etc.) 



In front of the halteres, there is a singular conical body, a little shorter 

 than the halteres, the homology of which I do n ot attempt to explain. 



Abdomen of the female with a circle of spines at the end. 



I possess only a single, very much injured, female specimen ; and if 

 I venture, nevertheless, to describe it, it is on account of its very marked 

 generic characters and its evident relationship to the Chilian genus 

 Mitrodetus. 



Ehaphiomidas episcopus n. sp., 9. — My only specimen having 

 been very much injured by moisture, I can say very little about its 

 natural color ; at present, it is uniformly black, opaque (originally, 

 it may have been gray) ; the three last abdominal segments shin- 

 ing ; remains of long, brownish-yellow pile are visible on all parts of 

 the body ; short, black, appressed pile on the three last abdominal seg- 

 ments ; knob of the halteres yellowish-brown. Antennae dark brown, 

 the third joint reddish-brown, especially at the base. Front coxse black, 

 beset with long yellow pile ; femora dark brown ; tibiae reddish-brown, 

 with dense, recumbent yellowish pile, and some scattered, long, black 

 bristles ; tarsi brownish-red ; hind femora black (the middle legs and 

 the hind tibiae are broken off). Wings subhyaline, with a slight brown- 

 ish tinge ; the costal cell before the humeral cross- vein saturate yellow, 

 ish-brown ; the extreme proximal end of the marginal cell aild the 

 distal end of the costal cell have a similar brownish tinge. Length 

 about 25°"". 



Hab. — California. One female. 



