288 REVISION OF Tin: Ti:xi:i;i;iuNii).i: OF AMERICA, 



oval, broader behind the middle, m iderately convex and gradually declivous behind, the 

 li!\ emarginate, angles nol prominent. From Arizona and New M sxico. 

 I ,ength .85 inch. 



A. obovata, Euschides Lee, Ann. Lye. V. 127. 



Differs Prom the preceding in having the elytra much more broadly expanded behind 

 tin' middle, with acute rather prominent angles. The margin of the elytra is rounded and 

 indistinct. It is probable that future discoveries will unite the preceding species with 

 this one. 



Length .85 inch. 



A. convexicollis, Euscliicbs Lee., Px-oc. Acad. 7, 224. 



Differs from both the preceding species in the very narrow thoracic margin, and by 

 the greater convexity of the thorax, as well as the less breadth, as compared with the 

 length. The elytra are similar to those of conv .<■", and has distinct though not prominent 

 humeral angles. 



Rather common in Arizona. 



A. raarginata, Pelecyph. Lee., Ann. Lye. V. 128; rimatus, Lee., Proc. Acad. 7, 223; Philolithus ri 



■ ■ ii. i;i V. 158. 



One of our largest and at the same time a very variable species. 



Three varieties may he more especially noticed: 



Marginata, surface sparsely anil rather finely punctured, thoracic margin less stronedv 

 punctured and creiiulate. Elytra with an acute margin not extending to the apex. 



Uhnata, surface of elytra very coarsely and deeply punctured, thoracic margin very 

 strongly punctured and crenulate, disc convex. Marginal line ol elytra acute and extend- 

 in-' usuallj beyond three-fourths of their length. As compared with marginatw this spe- 

 cies is broader, and the elytra broader and less convex. 



Subcylindrica, thorax as in rimata; elytra elongate, strongly rounded on the sides. 

 sub-cylindrical and with a very short humeral carina; surface smooth, very finely 

 punctured. 



In all these forms the thorax is broader than long, sides strongly rounded and with a 

 flattened margin more or less crenulate. The disc i-, convex. The base is broadly lohed 

 at middle and with a broad impression opposite the scutellum. 



All these forms inhabit the desert regions bordering the Gila River of Arizona. 



Length 1.00-1.20 inch. 



A. gibbicollis, black, sub-opaque. Thorax broader than long, strongly gibbous, margin broad, thickened 

 and reflexed in front, gradual!} narrowing in base, apex deeply emarginate, angles acute, base rounded, and with 

 three deep impre ions scutellar and one on each side; elytra broadly oval, marginal carina distinct, base trun- 

 cate, angles distinct. Length .85 1.00 inch. 



A ver_\ distinct species, recalling the form of some of the Microschatiae by the strong 



