NORTH AMERICAN COLKOPTKRA. 23 



In this species as in subameus, the elytra vary in coloration. In 

 those in which the elytra are bicolored the side margin posteriorly 

 and the apex are somewhat reddish. The typical form has the al- 

 ternate intervals 1-3-5-7 pieeous, and a broad lateral S})ace of the 

 same color, from this the elytra may become totally black as in a 

 small series from Arizona, some of which were of the usual vittate 

 form, the others black. In the black forms the mesosternum is more 

 punctured and the median smooth space less evident. 



Occurs at Fort Yuma, Cal., eastward through Arizona, north to 

 Colorado and the Bitter Root Valley of Montana. 



Group G. 



Scutellum small. Anterior tibire tridentate, not serrulate above, 

 the anterior face smooth, the tarsi with first four joints equal in 

 length. Posterior tibiae fimbriate with equal spinules. Head not 

 tubeiculate. Thorax narrowed at base and with entire marginal 

 line. Elytra oval, the humeri dentiform. Mesosternum cai-inate 

 between the coxse. 



The narrowing of the thorax behind and the elytra narrowed at 

 base with dentiform humeri, give the species a fiicies almost peculiar 

 to them, and the thorax and elytra seem more distant at their bases 

 than in the vast majority of species. 



The following species are at present known : 



Clypeus distinctly dentate each side of the emargination. 



First joint of hind tarsus not as long as the next three ; punctuation of thorax 



intermixed iievadensij*. 



Clypeus angulate not dentate each side of the emargination. 



First joint of hind tarsus as long as the next three ; punctuation of tliorax 



coarse, irregularly scattered, not intermixed geiitilis. 



Clypeus feebly emarginate at middle, broadly rounded each side, geuaj not promi- 

 nent. 

 First joint of hind tarsus as long as the next three ; punctuation of tliorax as 

 in (jrntUis cribratiis. 



A. iievadeiisis Horn.— Oblong, pieeous or black, brown when immature, 

 shining. Antenna; brown. Head not tuberculate, surface rugose, especially in 

 front and at the sides. Clypeus slightly impressed in front, broadly not deeply 

 emarginate, on each side denticulate, the sides arcuate, geuiB moderately jn-onii- 

 nent and subacute. Thorax broad, widest slightly in front of middle, sides ar- 

 cuate, narrowing to base, hind angles broadly rounded, base arcuate, basal mar- 

 ginal line deep; disc convex, sparsely punctate with coarse and fine punctures 

 intermixed. Elytra oblong oval, slightly narrowed at base, the humeri slightly 

 dentiform, disc convex, moderately deeply striate, striffi moderately coarsely and 

 closely punctate, intervals feebly convex, sparsely punctulate. Body beneath 



