COLEOrXERA. 93 



there appear to be many good characters which may be employed for 

 purposes of classification, amongst others the enhirgement or not of the 

 10th joint of the antennae, the presence or not of spongy-pubescent 

 foveae on the occiput, the terminal spur of tlie posterior tibiae — 

 already used by Dr. LeConte — and the great variety in the modifi- 

 cations of the front in the males. In dcnticollis and virginicR the 

 general forms of body and antennae are so similar that they could 

 scarcely be separated, but the heads in the males are entirely different 

 in the character of the frontal and clypeal modifications. 



EUPLECTINI. 



The very minute insects included in this group form a very large 

 and important section of the singular family Pselaphidae, and bear a 

 very striking similitude to several genera of Staphylinidae, their 

 general resemblance to the genus Edaphus being most remarkable 

 and unaccountable ; the latter may, however, be distinguished by 

 tiieir flexible and retractile abdominal segments, which are seven in 

 number, while in the present group they are six in number and com- 

 paratively rigid; the minute structural characters are, of course, of an 

 entirely different nature. 



They appear to be rather rare as a rule, and are only occasionally 

 met with, which is due, probably, to their comparatively secluded and 

 little known habits, and their very small size; many new species and 

 genera are undoubtedly yet to be discovered within the territory of 

 the United States. The sexual characters are well marked, and 

 occasionally present very curious structures in the males ; these char- 

 acters are not made use of to any great extent in the following scheme 

 of classification, but are generally mentioned incidentally wlien suffi- 

 ciently interesting. 



The material employed is tiiat contained in the cabinet of Dr. 

 LeConte, together with a still larger set kindly communicated by 

 Messrs. E. A. Schwarz and H. G. Hubbard,- of Washington, and also 

 a few specimens in my own collection. In the second mentioned 

 was included one entirely new genus not contained in the collec- 

 tion of Dr. LeConte. The genera here considered are those having 

 but a single tarsal claw, and may be distinguished by the following 

 table, this being intended as a continuation of the one given in the 

 Classification of the Coleoptera of North America, Sm. Misc. Coll. 

 No. 507. 



Cont. Part II. 3 December, 1884. 



