xxxiii, '22] ENTOMOLOGICAL NEWS 269 



thoracic depression distinct and complete monticola Malloch. 



-Third tergite not flared at apex 2 



2. The curved linear depression of thorax extending from humerus to 

 the transverse median depressed line not distinct except near the lat- 

 ter ; third sternite distinctly longer than wide 3 



-The curved linear depression distinct and complete 5 



3. Hind femur with two black bands one just beyond middle and the 

 other at apex ; humeri pale yellow ; disc of mesonotum black, entirely 

 without vittae ; fore and mid tarsi yellow biannulata Malloch. 



Hind femora yellow, without black annuli ; thorax black or yellow, 

 with three or more or less distinct vittae ; apical two segments of 

 fore and mid tarsi black or brown 4 



4. Third antennal segment yellow campanulata Robertson. 



-Third antennal segment black or fuscous rufiventris Loew. 



5. Anterior width of frons about one-third of the head width; third 

 sternite distinctly wider at apex than long in middle ; inner cross- 

 vein not more than two-fifths from base of discal cell; scutellum 

 usually with more than two long sctulose marginal hairs, 



infuscata Loew. 



Anterior width of frons much less than one-third of the head width ; 

 scutellum with two setulose marginal hairs 6 



6. Scutellum distinctly transverse apically, the two long setulose hairs 

 separated by more than half the width of scutellum ; third sternite 

 longer than wide 7 



Scutellum regularly rounded apically, the two setulose hairs sepa- 

 rated by less than one-fourth of the basal width of scutellum. .. .8 



7. Hind femur conspicuously compressed on lower half apically, widest 

 part distinctly beyond middle ; thorax black, abdomen rufous 



occidentalis Malloch. 



Hind femur very slightly compressed apically, widest part close to 

 middle; thorax and abdomen yellow punctata Cole. 



8. Fifth (fourth visible) tergite with a shallow transverse rounded 

 concavity before apex which causes the tip of the segment to flare 

 upwards very slightly, the hairs on this segment and on fifth sternite 

 long and soft ; third sternite wider than long ; a robust species, 

 about 8 mm. in length armatipes Malloch. 



Fifth tergite normal in shape; third sternite longer than wide; 

 smaller species, not over 6 mm. in length 9 



9. Fore and mid tarsi with the apical two segments deep black, 



keeniana Williston. 

 Fore and mid tarsi yellow, the apical two segments hardly darker, 



flavimana Malloch. 

 Sphegina lobulifera sp. n. 



$. Shining black, antennae, lower half of fact- and a broad fascia 

 on basal half of third tergite of abdomen yellow. Legs yellow, apical 



