THE CANADIAN ENTOMOLOGIST. 227 



Pterandrena, Robt. 



Joint 3 of the antennae shorter than 4 + 5 or as long i . 



Joint 3 longer than 4 + 5 7. 



1. Joint 3 = 4 + 5- 



Fovea very broad, extending nearly to the lateral ocellus 2. 



Fovea narrow, not much wider than one-half the distance between 



lateral ocellus and eye 3. 



Fovea very narrow, its width about equal to one-half the distance 



between the lateral ocellus and eye 6. 



2. Clypeus densely indistinctly punctured ; pubescence on dorsulum not 



abundant, the surface nearly bare oiiiscicolor. 



Clypeus sparsely indistinctly punctured ; pubescence on dorsulum 

 abundant, the sculpture hidden albuginosa. 



3. Dorsulum distinctly tessellate punctate pallidiscopa. 



Dorsulum not distinctly tessellate punctate 4. 



4. Abdomen distinctly fasciate. 



Scopa thin, the hairs straight nudiscopa. 



Scopa dense, the hairs curved 5. 



5. Fovea with pale pubescence ; dorsulum black pallidifovea. 



6. Process emarginate, abdomen purplish complexa. 



7. Fovea long, extending below the insertion of the antennas, usually the 



lower end is distinctly outlined ; middle metatarsus about as wide 

 as the posterior metatarsus. 

 Abdomen black. 



Abdomen not fasciate ; scopa compact erigenoides. 



Abdomen fasciate . . 9. 



Abdomen bluish or greenish . . . .• 8. 



8. Scopa pale, whitish or brownish. 



Scopa whitish. 



Abdomen greenish ; clypeus almost impunctate, dull, almost 



hidden by pubescence , crypta. 



iVbdomen bluish, clypeus not strongly punctured, dull, nearly 



bare territa. 



Scopa brownish ; clypeus not hidden by pubescence acrypta. 



Scopa black. 



Clypeus distinctly punctured ; black; dorsulum and basal segment 

 of abdomen with pale pubescence nigrocxrulea. 



9. Dorsulum punctured ; enclosure not closely rugose, nearly 



smooth tiudhtiediocornU. 



