868 PROCEEDINGS OF THE ACADEMY OP 



posticis subacutis ; elytris apice late rotundatis, abdornine paulo brevioribus. 

 Long. -2 mm. 



Keokuk, Iowa, Dr. Brendel. This species agrees with the figures and 

 descriptions of the European L. testaceus, and I have had no opportunity, 

 by comparing specimens, to observe the differences which probably exist. 



My object in describing the species is not only to make known the dis- 

 covery of the genus on this continent, but to call attention to some hitherto 

 unnoticed characters which seems to indicate that its place is not in the family 

 Silphidae, in which it has been thus far classed. 



The head resembles very much that of a Hydrophilide, Philhydrus or Cer- 

 cyon, for instance, the upper surface being slightly convex, not narrowed 

 anteriorly, but broadly rounded, both on the sides and in front; the labrum is 

 broad, transverse and not prominent, the mandibles do not project; the anten- 

 nae are inserted on the under surface of the sides of the front, slender, longer 

 than the head and thorax ; the first joint is as long as the two following united, 

 the second is shorter, but scarcely thicker than the third ; the outer joints are 

 very slightly thickened ; all the joints appear equally opaque and pubescent ; 

 the eyes are entirely wanting ; the mentum is large, slightly concave, with the 

 hind angles acute, produced backwards over the gula, forming small carinas ; 

 the suture between the mentum and gula is distinct, but not as obvious as 

 usual ; the prothorax beneath is quadrately emarginate in front, s that 

 the anterior angles project under the head; the anterior coxae are oval or 

 rounded, not prominent ; the cavities are open behind, almost separated by 

 the prosternum, and externally furnished with a narrow fissure, to the end of 

 which the prosternal suture runs ; the middle coxae are small, separated by a 

 narrow carinated mesosternum ; the trochantin is visible, and the side pieces 

 extend to it ; the hind coxae are flat, and not very large ; the tibial spurs are 

 long and slender, and all the tibiae are sparsely spinous ; the tarsi are all five- 

 j.ointed, and the fourth joint is slightly oblique beneath, and furnished with a 

 dense brush of hairs ; the first joint of the hind tarsi is as long as the three 

 following united ; the abdomen is flat, with the sixth joint short, but distinct. 



It is to be observed, from the notes given above, that this genus differs from 

 Silphidae by 1st, the form of the head, and the insertion of the antennae, 

 2d, the form of the mentum, 3d, the form and arrangement of the anterior 

 coxae, 4th, the structure of the fourth joint of the tarsi ; all of which are 

 characters of fundamental importance. It agrees with Hydrophilidae in the 

 form of head, insertion of antennae, general arrangement of mentum, gula 

 and prosternum, but differs by the regular antennae, not prominent anterior 

 coxae, aud structure of the fourth joint of the tarsi. The relations with 

 Mycetophagidae, to which it bears a superficial resemblance, and Cryptophagi- 

 dae, are too remote to be worthy of analysis. With Nitidulidae, especially the 

 genera having large mentum, it might also be considered to have some 

 affinity, but the fourth joint of the tarsi is not small, the anterior coxae 

 have no trochantin, and their coxal cavities are partially confluent and open 

 behind. 



I therefore infer that Leptinus is a highly specialized type, representing a 

 distinct family, having less affinity with Silphidae than with Hydrophilidae. 



Dr. Brendel observes in a letter, " This insect I found under a log in a mouse 

 nest, in company with fleas ; in the neighborhood were yellow ants, of the 

 same kind with which C e o p h y 1 1 u s lives." 



ANISOTOMA 111. 



A. conferta, ovalis, convexa castanea nitida, capite thoraceque minus 

 dense subtiliter punctatis, hoc brevi, lateribus magis rotundatis ; elytris seriatim 

 confertim punctatis, subtiliter parce obsolete transversim strigosis, stria sutu- 

 rali sola impressa ; pedibus testaceis. Long. 3 mm. 



Mas tarsis anterioribus articulis 2 4 paulo dilatatis ; femoribus posticis 



[Dec. 



