246 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



Read subglobular ; occiput but slightly tumid ; oral opening oval, 

 slightly oblique; front projecting very little in the profile; epistoma re- 

 treating below the antennae, comparatively long (longer than in An- 

 thrax) and broad, nearly flat; cheeks exceedingly narrow, linear, the 

 eyes being nearly in contact with the mouth ; eyes very large, occupying 

 the whole side of the head, and descending on the under side to the very 

 edge of the mouth ; they are (as in Anthrax) somewhat reniform, with 

 a linear impression, starting from the sinus of the occipital orbit and 

 interrupted about the middle ; in the male, the eyes come in contact for 

 a short distance in front of the small ocellar triangle ; in the female, 

 they are separated by an interval, which is not greater than the inter- 

 val between the roots of the antennae; frontal triangle, in the male, 

 very large, nearly flat; the pubescence on front and epistoma is short, 

 denser on the latter than on the former. 



Antenna?, in a profile- view of the head, are inserted about its middle ; 

 the two basal joints are exceedingly short, concealed in the pubescence; 

 the third joint, broad at base, becomes suddenly contracted, long, linear, 

 styliform, truncate at the end, the truncature bearing a minute joint, 

 with a bristle at the end. 



Thorax rounded, clothed with a very delicate, even, silky, erect, and 

 moderately long pubescence ; only a single delicate bristle is perceptible 

 on each side in front of the wings, and a few on the antescutellar 

 tubercle (they are of the same color with the pubescence) ; scutellum 

 rather broad. 



Abdomen, in the male, narrower than the thorax, and not much longer, 

 cylindrical, the seventh segment being only a little narrower ; in the 

 female, the abdomen is a little longer than the thorax, and nearly as 

 broad, gradually attenuated posteriorly. The segments do not differ 

 much in length, the second being but a little longer ; in the female, the 

 seventh, at the end, bears a dense circle of appressed hairs, their ends 

 converging, and closing the anal opening. 



Legs moderately long, clothed with scales, and beset with spines ; pul- 

 villi distinct. 



Wings of moderate length and breadth, narrower than in most species 

 of Anthrax ; venation like that of an Anthrax, except that the bifurca- 

 tion of the second and third veins takes place very early, at the same 

 distance from the root of the wing as the proximal end of the discal 

 cell ; the praefurca is but one-half longer than the great cross- vein ; the 

 small cross- vein is about the middle of the discal cell ; the curvature of 

 the second vein at the end and of the anterior branch of the third 

 vein are very much like those of an ordinary Anthrax (A. alternata or 

 sinuosa); costal enlargement small; a distinct, apparently coriaceous, 

 epimeral hook, as in Anthrax. 



Triodites, in Greek, means a street-lounger. 



Triodites mus n. sp., <? 9 . — Uniformly clothed with whitish-gray pile; 

 face with white pile ; wings hyaline. Length 8-9 mm . 



