74 GEO. H. HORN, M. D. 



Under the name dccoloratus I have phiced as synonyms sereus Mels. 

 and hemipodus Say, the former being merely the usual form of female, 

 the latter a larj^er development of the same sex. The specimen of 

 hemipodus described by Leconte (Revis. Elat. p. 449), is an abnormal 

 specimen, not only in the thoracic sculpture but also in the vague 

 elytral impressions. 



This species occurs everywhere in the Atlantic region as far west as 

 Missouri, but I have never seen any from the Gulf States. 



A. meiiinoniiis Herbst. — -This species presents a range of variation in 

 form parallel with that of bilobatus. Its general characters are: Color piceous 

 to pale brown, legs always paler, surface sparsely clothed with brownish pubes- 

 cence. Thorax moderately densely punctured but variable in the sexes, the 

 disc more convex in the female, hind angles not divergent, rather strongly 

 carinate, the carina divergent from the margin ; beneath rather coarsely punc- 

 tured but with a smooth space of variable extent posteriorly ; prosternal mucro 

 flexed at tip, mesosternuni not prominent. Elytra moderately deeply striate, 

 the striae punctured, intervals moderately convex, punctulate. 



Males. — Thorax less convex more sparsely punctured, sides nearly straight, 

 form nearly square. Elytral strise equally deep on the disc and sides. 



Females. — Thorax convex, moderately densely punctured, sides usually 

 moderately arcuate. Elytral strise often less deep near the suture. 



Under the name memnonius I unite in addition to those already 

 placed there, haridius Say, and hrevicoUix Cand., the former being the 

 female and the latter merely a less developed form of the species. 



Occurs from Canada to Georgia and westward to Colorado. It 

 varies in size from .50 — 1.02 inch; 13 — 26 mm. 



A. bilobatus Say. — Under this name are included those forms in which 

 the hind angles of the thorax are not carinate and the intra-angular incisure 

 of the basal margin is absent. The form, especially in the thorax, varies in 

 the sexes and has given rise to the synonymy noticed further on. The males 

 are more slender, the thorax longer than wide, the sides straight and usually 

 convergent in front. In the females the thorax is nearly square, sometimes 

 longer than wider, the sides more or less arcuate and rarely slightly sinuate 

 behind. The convexity of the thorax also varies sexually being more convex 

 in the female but this difference is by no means so obvious as the form. The 

 punctuation is moderately coarse but not very dense but varies in both respects. 

 The elytra are striate, the striae coarsely punctured near the base becoming 

 finer toward the tip, the intervals are convex, irregularly biseriately punctu- 

 late. In most of the females the strise nearest the suture are much less deep 

 than in the males. The flanks of the prothorax are coarsely punctured but 

 shining, the punctures being scarcely less dense posteriorly than in front. The 

 prosternal mucro is flexed at tip, the mesosternum not prominent. The color 

 varies from rufo-testaceous to pale brown and the surface is sparsely clothed 

 with pale brownish pubescence. Length .50 — .6-1 inch; 13 — 16 mm. 



It is not possible to define varieties accurately, but the following 

 notes may render intelligible some of the described forms. 



