Goleopterological Notices, VII. 351 



is less narrowed behind the eyes, with the tempora more rounded ; 

 it occurs in Iowa and may be named intermedia. 



SCYDM^NID^. 



There is undoubtedly a strong resemblance in habitus between 

 the Scydmsenidiie and Pselaphidse, but whether this similarity in- 

 dicates a real affinity due to community of descent, or has been 

 gradually brought about in widely diverging descent-stems by 

 reason of common habits and environments, may be a debatable 

 point. The principal reasons for believing that the latter may be 

 the case, are the entire or subentire elytra, and the purely and 

 exceedingly constant pentamerous tarsi in the most widely di- 

 vergent forms, both of these characters being completely foreign 

 to the Pselaphidse. The truth is probably, that the Scydmaenidse 

 have developed from staph3dinid architypes, but along lines 

 widely diverging from the Pselaphidse. The abdominal sutures 

 are straight, as a rule, in the Scydmsenidse and arcuate in the 

 Pselaphidse, but in the tribe Eumicrini, which is distinguished 

 from all other scydmaenids hy a large vertical pygidium and 

 pselaphidous hind trochanters, the abdomen cannot be distin- 

 guished from that of a purely typical pselaphid, the sutures be- 

 ing strongh^ arcuate. 



It is not necessar}'^ to dwell at length upon the general ana- 

 tomical characters of the exoskeleton, as most of these will be 

 brought out in the tables given below, but it may be proper to 

 jDoint out some of those which seem to be either peculiar to the 

 Scydmsenidse, or prominent features of this family. The head is 

 borne on a constricted neck, except in the Cephenniini, which con- 

 stitute for this reason a XQvy isolated tribe. In two cases, 

 Chevrolatia and Lophioderus, the neck is not abruptly con- 

 stricted, but is elongated and deeply excavated upon its dorsal 

 surface. The eyes are present in every species known to our 

 fauna, except Cephennium anophthalmicum ; they are usually 

 rather finely faceted. The occurrence of fovese on the vertex is 

 very rare in comparison with the Pselaphidse, but when present 

 they are usuallj'^ of generic import, as for example in Yeraphis 

 this genus being otherwise proved distinct from Eutheia by the 

 strong carination of the mesosternum. The mandibles are gen- 

 erally small, but in the European Leptomastax, become remark- 



