50 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



shallowly, angularly emarginate, the lobes broadly round- 

 ed; third and fourth segments of antennas subequal; ocellar 

 basin not indicated in front of median ocellus; median 

 fovea large with flaring sides; saw-guides with their upper 

 and lower margins converging, obliquely truncately 

 rounded at apex; body black, with mandibles, clypeus, 

 labrum, collar, tegulae, base of wings, and legs, except 

 infuscations on femora, hind tibiae, and more or less of their 

 tarsi, white. Length 7 mm convexa 



6. Ocellar basin extending to median ocellus 7 



Ocellar basin not extending to median ocellus, at most only 



indicated adjacent to median ocellus or median fovea.... 17 



7. Clypeus black 8 



Clypeus white 12 



8. Ocellar basin dumb-bell-shaped, constricted to a mere line 



at middle, broad and pit-like adjacent to median ocellus; 

 median fovea an elongate pit; antennal furrows interrupted 

 on the middle of the front; ocellar and interocellar fur- 

 rows distinct; clypeus emarginate with a distinct tooth 

 at middle; third segment of antennas longer than the 

 fourth; saw-guides with upper margins straight, lower 

 margins converging, and broadly obliquely rounded at 

 apex; body black, with labrum, clypeus, collar, tegulae, base 

 of wings, and "legs beyond apices of coxae, white. Length 



6 mm callida 



Ocellar basin not dumb-bell-shaped, of approximately the 

 same width throughout 9 



9. Clypeus with a broad, convexly rounded median ridge, occu- 



pying almost one-third of the width of clypeus; antennal 

 furrows interrupted on the middle of the front; median 

 tooth of clypeus distinct^ shorter than lateral lobes, 

 lateral lobes broadly rounded; ocellar furrow linear, in- 

 terocellar furrow broad and distinct; third segment of 

 antennae almost as long as fourth and fifth together; saw- 

 guides convex above and below, slightly obliquely rounded 

 at apex; body black, with collar, tegulae, front and middle 

 legs below knees, and hind tibiae beneath, white. Length 



6 mm cava 



Clypeus with a fine linear median carina; antennal furrows 



more or less distinct throughout 10 



10. Clypeus tridentate, median tooth as long as lateral angles, 

 broadly, shallowly emarginate, lateral angles rounded, me- 

 dian ridge low, not reaching dorsal margin of clypeus; 

 postocellar area uniformly convex; ocellar and interocellar 

 furrows distinct; third segment of antennae longer than 

 fourth; saw-guides slightly convex above, broadly con- 

 vexly rounded below and at apex to a blunt point above; 



