June-Sept., 19 19. ] Olsen : Idiocerus cognatus. 127 



talia and in the color it differs from /. rufus. The variety cingulatus 

 comes closer in color, but its structure is too indefinitely described to 

 permit of comparison. The following description will further serve 

 to identify it. 



Face one-fifth wider than long; clypeus nearly one-half longer 

 than broad at apex, about twice as long as at its base, distinctly 

 swelling lateral at the truncated apex; lorae longer than clypeus 

 and its width four-fifths that of the clypean apex; gense depressed 

 beneath the eyes, the lateral margins slightly convex just below the 

 eyes, then more or less straight attaining the tip of the clypeus; front 

 as broad as long; antennae without any disk. Vertex a trifle shorter 

 on the middle than next to the eyes; the distance between the eyes 

 more than four times the length of the center of the vertex; fine 

 transverse rugosity barely visible. Pronotum more than twice as 

 long as broad. Scutellum one and one-half times as broad as long, 

 with a decided impression on the disk. Face, vertex, pronotum and 

 scutellum very finely and evenly granulated. Elytral veins prominent 

 and with punctures, four apical and three anteapical cells; inner 

 anteapical cell more than twice as long as the outer one. Last 

 ventral segment of the male twice triangularly excavated, leaving a 

 prominent, triangular, central tooth with a slightly rounded tip, the 

 whole segment longitudinally rugulose. Plates long and twisting 

 near the apex, terminating in long, fine, white hairs. Last ventral 

 segment of the female strongly rounding and without any median 

 notch, ovipositor slightly longer than pygofer. 



Color of male. Face from greenish white to strong yellow in the 

 highly colored specimens; ocelli yellowish brown, encircled with pale; 

 eyes dark red, sometimes nearly black ; basal segments of the antennae 

 the color of the face, the long, tapering filamentts rapidly recoming 

 quite dark. Vertex like the face, with a tendency to be slightly 

 darker discoidally and devoid of any spots. Disk of pronotum with a 

 bluish-gray cast; margins paler, usually with a pair of faint dark 

 spots on the anterior half. Scutellum yellow with the discal im- 

 pression dark, in some specimens quite strongly marked ; basal angles 

 sometimes marked with brown triangles. Elytra transparent milky 

 white, with the area from the base to about the level of the tip of 

 the scutellum a trifle smoky; a stronger smoky brown area located 

 from just behind the middle to before the tip of the clavus, extending 



