66 MEMOIRS ON THE COLEOPTERA 



prothorax narrower, parallel and feebly, evenly arcuate at the sides 

 from apex to base, and not inflated and strongly rounded as in the 

 normal form of the species; as there are but few other points of 

 difference, I am uncertain as to the taxonomic meaning of this 

 peculiarity, though it imparts a distinctly different facies to these 

 two individuals. The genus Calosoma, when fully collected, will 

 prove almost as troublesome to us as Carabus is to the European 

 systematists. 



Callisthenes Fisch. 



We need only take a general glance at Calosoma and Callisthenes as 

 a whole, to note a very perceptible difference in habitus extending 

 consistently through both groups of species, and Callisthenes should 

 therefore be retained for those Calosomids having oval elytra and 

 broadly rounded humeri, generally signifying absence or great curtail- 

 ment of the wings. But disregarding these external features, the 

 genus is proved conclusively to be distinct because of antennal struc- 

 ture. It will be observed that the distal joints in Calosoma are virtu- 

 ally uniform in their dense pubescence, while in Callisthenes the outer 

 joints are in great part glabrous on their flattened faces, the lines 

 separating these glabrous spaces from the large pubescent areas 

 being very sharply defined. The head is generally less developed 

 than in Calosoma, and such forms as moniliattis Lee., which possess 

 the three series of elytral elevations as in Calosoma cancellata, and 

 the similarity to which in elytral sculpture may perhaps have given 

 rise to doubts concerning the validity of Callisthenes, are not really 

 allied to cancellata at all ; they differ not only in the rounded humeri 

 but in the very much smaller head, form of the basal part of the 

 prothorax, which is exactly as in the zimmermanni group of Callis- 

 thenes, and in the distinctive antennal structure; furthermore, a 

 closer examination will show that the elytral sculpture, between the 

 rows of elevations, is wholly different from that of the cancellata 

 group of Calosoma. 



The species of Callisthenes are very numerous in the western parts 

 of North America, but are unknown east of the Rocky Mountains 

 to any considerable distance and they are particularly abundant 

 in California. The following seem to be hitherto unnamed : 



Callisthenes concinnus n. sp. Oval, convex, rather more elongate 



