34 STUDIES IN NORTH AMERICAN MEMHRACI I >. E 



Clypeus triangularly produced beyond the line of the 

 cheeks, 6. 



6. Metopidium flat or concave between the suprahumerals, 



sometimes a very little convex at the middle, 7. 



Metopidium transversely sinuated between the suprahu- 

 merals, the horns slender and strongly recurved, 9. 



7. Larger, 8-10 mm.; suprahumerals long, subterete, sloping 



upward and curved backward, 5, taurina Fitch. 



-. Smaller, 7-8 mm. ; suprahumerals shorter, triangular, ab- 

 rupt, horizontal, a little curved backward, 8. 



8. Pronotum hairy; suprahumerals rather long, terete or 



nearly so; ultimate ventral segment of the female acutely 

 emarginate; venter of the male concolorous; inhabits east 

 of the Rocky Mts. 9, borealis Fairm. 



Pronotum smooth; suprahumerals short, acute-triangular, 

 scarcely terete ; median notch of last ventral segment of 

 the female rounded at apex; venter of male black; in- 

 habits California, n, albido-sparsa Stal. 



9. Metopidium and dorsal line ferruginous brown, the carinse 



piceous; length 8 mm., 7, constans Walk. 



-. Green or greenish, the dorsal carina a little rufous, incli- 

 ning to piceoiis, 8, Palmeri V. D. 



10. Suprahumerals short-triangular but distinctly produced, n. 

 Suprahumerals reduced to a mere angle, 13. 



11. Metopidium transversely flat between the suprahumerals, 



its median carina distinct ; face with conspicuous vertical 

 striae between the ocelli and eyes, 



12, brevis Walk, female 



Metopidium transversely convex between the suprahu- 

 merals, 12. 



1 2. Sides of the metopidium slightly diverging upward, rec- 



tilinear to the short abrupt suprahumeral angles; face 

 flat, longitudinally striate at base ; apical margins recti- 

 linear, medium carina of metopidium almost obsolete, 

 carinate edges pale, 13, brevicornis Fitch 



Metopidium low, its sides vertical for half its height, then 

 abruptly diverging to the suprahumeral angles, median 



