NOETH AMEEICAN BUPEESTID BEETLES 11 



43. Elytra with distinct, uniformly distributed, short, white pubescence. 



(38) olivaceouiger Fisher. 



Elytra without distinct pubescence, except sometimes for a few white hairs 



along the sutural margins near apex 44. 



44. Vertical portions of second abdominal segment glabrous 45. 



Vertical portions of second abdominal segment more or less pubescent — 46. 



45. Above dark blue to bluish black; tips of elytra rather broadly rounded, 



rarely acute (39) acutipennis Maunerheim. 



Above aeneous to olivaceous black ; tips of elytra more acutely rounded ; 

 pronotum more deeply depressed at middle anteriorly. 



(40) auricomus Frost. 



46. Elytra with the tips usually broadly rounded ; pubescence on abdomen and 



vertical portions of abdominal segments white or yellowish white. 



(41) quadriimpressus Ziegler. 

 Elytra with the tips more acutely rounded ; pubescence on abdomen and 

 vertical portions of abdominal segments usually golden yellow. 



(40) auricomus Frost. 



47. Vertical portions of abdominal segments (except sometimes the second) 



conspicuously pubescent 48. 



Vertical portions of all abdominal segments uniformly, but not conspicuously 

 pubescent 50. 



48. Prosternal lobe broadly subtruncate in front ; elytra black, with six very dis- 



tinct golden yellow pubescent spots (42) auroguttatus Schaeffer. 



Prosternal lobe emarginate in front ; elytra brownish black, with a more 

 or less distinct aeneous or cupreous tinge, and with six feebly indicated 

 pubescent spots, some of which are frequently obsolete 49. 



49. Front of head densely pubescent, the pubescence nearly obscuring the sur- 



face; elytra with the tips rather broadly rounded (43) granulatus (Say). 



Front of head not densely pubescent, the surface distinctly visible ; elytra 

 with the tips acute, or narrowly rounded (44) qitadriguttatus Gory. 



50. Elytra with pubescent spots, usually only feebly indicated 51. 



Elytra without pubescent spots 54. 



51. Scutelluin transversely carinate ; tips of elytra narrowly or rather acutely 



rounded 52. 



Scutellum not transversely carinate ; tips of elytra very acute. 



(2) nevadensis Horn. 



52. Above feebly shining or subopaque ; sides of abdomen beneath broadly, 



densely, uniformly pubescent. Host: Willow (45) niveiventris Horn. 



Above strongly shining 53. 



53. Sides of abdomen beneath sparsely pubescent, the pubescence forming more 



or less distinct spots ; male with the first abdominal segment flattened, 

 and the second with a vaguely depressed smooth median space on basal 



half. Host: Willow (46) fulminans Fisher. 



Sides of abdomen beneath very sparsely pubescent, the pubescence not form- 

 ing spots ; male with the first abdominal segment feebly concave, and the 

 second with a broad, moderately deep, smooth depression at the middle. 

 Host: Poplar (47) populi Fisher. 



54. Male with the front of head densely pubescent, nearly concealing the surface. 



(48) betulae Fisher. 



Male with the front of bead not densely pubescent, the surface distinctly 



visible 55. 



55. Above uniformly dark reddish cupreous (49) pensus Horn. 



Above olivaceous black to bluish gray 56. 



2305— 2S 2 



