248 J. L. LECONTE, M. D. 



and iiiflexed flanks finely margined. Elytra convex, wider than the prothorax, 

 Length 2.6 mm; .10 inch. 



% . — Sixth ventral produced into a large broadly and deeply excavated plate ; 

 seventh and eighth with a broad and deep longitudinal concavity. 



Louisiana, Arizona, California. The excavation of the broud plate 

 of the sixth ventral produces two large compressed curved wings, 

 which are much more developed in the Western specimens than in 

 the one from Louisiana. The head of the $ is a little smaller than 

 that of the % , more rounded behind the eyes, and less truncate at 

 base; in consequence of this great development of the sexual arma- 

 ment of the sixth segment, the seventh which is the more complex 

 one in the next species, is simply broadly concave, and without lateral 

 processes. 



3. A. sphsericollis, Er. Staph. 813, tab. 2, f. 5; Lathrobium sph. Say, 

 Trans. Am. Phil. Soc. iv, 455; ed. Lee. ii, 570; Falagria globosa, Mels. Pr. Ac. 

 Nat. Sc. Phila. ii, 30; Falagria longicornis, Sachse, Ent. Zeitung. Stettin, 1852, 

 116; F. amabilis, Sachse, ibid. 



Atlantic and Pacific slopes, Massachusetts to Florida, Texas, Kansas, 

 Arizona and California. Varies greatly in color, and somewhat in the 

 form of the prothorax, which is occasionally nearly as wide as the 

 head, and less oval than usual; sometimes on the other hand, a little 

 longer than wide and regularly oval. 



The color also varies from blackish piceous, with the base of the 

 antennae and legs testaceous, but the thighs tinged with fuscous; to 

 bright rufo-testaceous, the abdomen dark, and the head and outer 

 joints of the antennae fuscous; the under surface, except of the 

 prothorax is also dark. 



In a S of this last mentioned form the plate of the sixth ventral 

 segment is less developed than in the others, and does not project 

 downwards, so as to form a membranous concavity on the terminal 

 part of the segment. I consider this, however, as rather a want of 

 development, than as indicating specific distinction. 



The description of Dr. iMelsheinier would not be recognized as 

 belonging to this species, as the imperfect lenses he used, and the 

 bad condition of the specimen caused it to appear to hiiu minutely 

 punctured. 



% . — Sixth ventral segment with a short broad process, forming a 

 ciliated edge margining a vertical membranous concavity; seventh 

 ventral very deeply concave, with a broad compressed triangular wing 

 each side, which is directed towards the middle; eighth segment 

 slightly concave. 



