244 THK CANADIAN ENTOMOLOGIST. 



Front wing with veins beyond IV, not obsolescent; cell III 4 at least 



nearly twice as long as III, i. 



i. Labrum flat, ciliate ; cell III- much wider than long, usually less 

 than y' 2 as long as 1 1 1 4 ; ceil III,+ 2 pointed on costa ; vein 

 IV, near end of cell III S ; metathorax usually strongly rugose; 

 abdomen usually more or less red ; hind spur finely pectinate ; 

 hind knee plate obsolete ; rima on segment 5 obsolete . Sphecodes. 



Labrum at apex produced, laterally compressed, pectinate ; rima 

 present 2. 



2. Black or dull greenish ; segments of abdomen with apical pubescent 



fascise ; cell III I+2 subappendiculate ; vein IV 3 beyond the middle 

 or near end of cell HI.; hind knee plate lanceolate; vein a 



rather suddenly bent at lower third Halictus. 



Bright golden green, at least the head and thorax ; segments of 

 abdomen with pubescent fasciae basal or wanting 3. 



3. Metathorax sharply truncate, the truncation circular, bordered by 



salient rim ; hind spur with three broad spines ; hind knee plate 

 obsolete; cell III I+2 subappendiculate ; vein IV, beyond middle 



of cell III- Agapostemmn. 



Metathorax rounded posteriorly, at least above, the truncation, when 

 evident, subquadrate 4. 



4. Hind spur with 4-6 long teeth; cell III,+ 2 subappendiculate; vein 



IV, interstitial with III- , or entering cell III 4 ; vein a 

 rather strongly bent about the middle ; hind knee plate 



obsolete Augochlora. 



Hind spur finely senate; cell III,+ 2 usually pointed on costa; 

 vein 1V 3 usually interstitial with III, , rarely entering cell III 4 ; 

 vein a regularly arcuate ; hind knee plate present, 

 lanceolate Oxystoglossa. 



5. Front wing with vein III, not obsolescent; cell III, + 2 subappen- 



diculate ; vein IV, near end of cell III, ; hind spur finely serrate ; 

 insect unusually smooth and opaque ; segments 2-4 with basal 



pubescent fasciae Lasioglossum. 



Front wing with vein III, also obsolescent or absent; vein IV, near 

 end of cell III, or interstitial with vein III, 6. 



6. Black Evylaeus. 



Dull greenish or bluish, at least the head and thorax ; hind spur with 



3-5 long teeth 7- 



