246 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



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

 slightly oblique; front i)rojecting very little in the profile; epistoma re- 

 treating below the antennse, 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 ijubesceuce on front and epistoma is short, 

 denser on the latter than on the former. 



Antemue, 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 witli scales, and beset with spines ; pul- 

 villi distinct. 



Wings oi 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 pr?efurca 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™°^. 



