NORTH AMERICAN COLEOPTERA. 103 



front convex, moclera,tely densely punctured; clypeus (170) with a very broad 

 shallow emargination, arcuate each side ; thorax twice as wide as long, base wider, 

 than apex, sides very regularly arcuate, disc convex, very densely but equally 

 jiunctate ; elytra very little wider than the thorax, parallel, arcuately narrowed 

 at apical third, the margin serrulate, the apices very obtuse, exposing the tip of 

 the abdomen ; disc moderately convex and even, the basal fovea very faint, sur- 

 face very densely and equally punctate, the punctures a little finer than on the 

 thorax and with a tendency to form oblique strigse near the sides ; body beneath 

 moderately, densely punctate, and clothed with short white recumbent pubes- 

 cence, sides of abdomen more densely punctulate and pubescent, the margins of 

 the segments on each side sutures two, three and four smooth ; last ventral seg- 

 ment with serrulate margin ; prosternum rather strongly lobed in front ; anterior 

 femur without trace of tooth. Length .22 inch ; 5.5 mm. (Fig. 169.) 



3Ia}e. — Unknown. 



Female. — Prosternum flat, closely punctate ; the tibise all straight ; last ventral 

 segment (171) sinuately truncate ; last dorsal segment punctate, the tip emar- 

 giuate. 



This species is a diminutive in form of atrifasciata, and could 

 have been placed next to it if the last ventral segment had not ser- 

 rulate margins. I place it, however, among the subcylindrical spe- 

 cies, admitting at the same time that it shows a marked relationship 

 with debilis in the sculpture and pubescence of the under surface as 

 well as with atrifasciata in its general form. It is remarkalile in the 

 absence of femoral tooth, and while the specimen is a female it is not 

 probable that the male is otherwise, as I have not observed any dif- 

 ferences in all the other species in the form or size of the femoral 

 tooth between the sexes. 



One specimen, Arizona. 



Group VI. 



The species of the small grcjup here separated are of medium or 

 rather large size. They agree in having the thorax widest anteriorly, 

 the sides from the anterior third narrowed to base ; the prosternum 

 is not lobed in front, and in both sexes is nearly smooth along the 

 middle ; the last ventral segment has the margin devoid of serrula- 

 tions, although in several the edge is interrupted ; in the male the 

 apex is usually very deeply, almost quadrangularly emarginate. The 

 apices of the elytra are rather acute and more or less prolonged in a 

 spine. 



The following table will assist in recognizing the species : 



Thorax not sulcate at middle, or with a feeble trace of a depression. 



Lateral margin of last ventral segment abruptly interrupted 35. serea. 



Lateral margin of last ventral entire. 



