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



2. Wings smoky 3 



Wings hyaline 6 



3. Legs entirely black . 4 



Legs with tibiae yellowish, at least anterior pair in front 5 



4. Abdomen with venter pale; clypeus almost truncate at apex; 



frontal crest and sides of ocellar basin nearly obsolete, 

 indistinct; median fovea small, elongate; antennae with 

 third segment shorter than fourth; procidentia very mi- 

 nute and squarely truncate or broadly excavated at apex; 

 body black, with clypeus, labrum, cheeks, and bases of 

 mandibles, whitish; orbits tinged with rufous. Length 6.5- 



7 mm concolor 



Abdomen with venter yellowish white; clypeus very shal- 

 lowly emarginate; ocellar basin with rounded, indistinct 

 walls, frontal crest almost wanting; median fovea shallow, 

 elongate; antennal segments three to five subequal, the 

 fourth longest; saw-guides obliquely truncate' at apex; 

 body black, with the oral region, outer orbits, supraclypeal 

 area, pronotum in great part, and venter of abdomen, yel- 

 lowish white. Length 9 mm comstockii 



5. Clypeus rather broadly and shallowly emarginate; orbits 



pale; ocellar basin with distinctly defined walls; frontal 

 crest narrow, not extending on each side, slightly broken by the 

 deeply excavated, elongate median fovea; antennae with 

 third segment shorter than fourth; saw-guides somewhat 

 elongate, rounded at apex; body brownish black, with 

 supraclypeal area, orbits, oral region, angles of pronotum, 

 more or less of apical ventral segments, joints of legs, and 



most of anterior tibiae, yellowish. Length 8 mm gracilis 



Clypeus narrowly and rather deeply emarginate; orbits not 

 pale; ocellar basin with its lateral walls rounded; frontal 

 crest deeply broken by backward extension of deep, elon- 

 gate median fovea; antennae with third segment shorter 

 than either fourth or fifth; saw-guides elongate, slightly 

 tapering, rounded at tip ; body black, with supraclypeal 

 area, clypeus, labrum, cheeks, base of mandibles, and 

 angles of pronotum, yellowish white; anterior legs in 

 front from middle of femora, yellowish infuscated; venter 

 of abdomen, except apex, yellowish. Length 9 mm similis 



6. Abdomen black on venter 7 



Abdomen pale on venter 8 



7. Legs black except at joints; clypeus moderately and rather 



narrowly emarginate; ocellar basin with side walls rounded 

 and indistinct; frontal crest not extending laterally, slightly 

 broken by the shallow median fovea ; procidentia short, 

 squarely truncate, with sharp angles, keeled ; body black, 





