226 [JANUARY, 
Descriptions of Twenty new species of Coleoptera inhabiting the United States. 
By Joun L. Le Conte, M. D. 
The following are a few remarkable species of families which are so small as 
not to be of sufficient importance fora special essay, or else they belong to 
groups which, having already furnished material for synopses or monographs, 
are not sufficiently increased to need revision. Some new genera are proposed, 
the affinities of which, so far as made out, will be detailed below; the names of 
the families to which the new genera belong are appended to each. Species in- 
dicated from the Mexican Boundary, were collected by Mr. J. H. Clark, under 
Col. J. D. Graham, and were kindly communicated to me by my friend Dr.8. F. 
Baird. 
AnisomERA Brallé. (Dytiscide.) 
Palpi cylindrici, labiales articulo penultimo longiore; prosternum non com- 
presso-carinatum, postice productum; tarsi anteriores filiformes articulo ultimo 
elongato, postici parce ciliati, articulis 1mo 5toque elongatis, unguiculis binis 
zqualibus mobilibus. 
Having several specimens of a species of this interesting genus from New 
Mexico, I am able to complete the description of Brulle and Aubé, which were 
taken from a specimen deprived of its posterior feet. These organs are slender; 
the tibie are slightly ciliated internally with long hairs, and armed at the tip 
with two slender, subequal spurs; the posterior tarsi are not longer than the 
tibiz, slightly compressed and sparsely ciliated; the first joint is as long as the 
second and third; the 2d, 3d and 4th are nearly equal ; the Sth is a little shorter 
than the 3d and 4th, not narrowed towards the extremity; the claws are equal 
and moveable. In the male, the first three joints of the anterior and middle 
tarsi are slightly dilated, and furnished beneath with feathery papille, very 
much as in Platynus. The posterior tibie of the female are scarcely ciliate. 
This genus appears quite as closely allied to Agabus and Copelatus as they 
are to each other. The form of the thorax would indicate, however, that it 
must be received as a distinct genus, but the characters, on close examination, 
appear to be of little value; the best differences are found in the elongation of 
the last joint of the anterior and middle tarsi, the smaller size of the spurs of 
the posterior tibiz, and the more regular form of the posterior tarsi, which are 
not attenuated at the apex. The middle lobe of the mentum in the species here 
described is broad, short, and very obsoletely sinuated, while the mentum of 
Anisomera is described as having the middle lobe slightly prominent in the 
middle; this character must be re-examined with other specimens, as, if it be 
correctly described, the present species cannot be associated with the type of 
the genus; the prosternum is less compressed than in Copelatus. Agabus is 
described as having the prosternum strongly compressed and carinate; this 
structure is found in A. taniatus Avdé, and many others, but is hardly to be 
observed in A.striatus Awbé. JI would also observe that Agabus an- 
gustus Lee. (Agassiz. Lake Sup.,213) by having the thorax much rounded 
before, and nearly parallel behind the middle, shows a tendency towards the 
peculiur form seen in Anisomera. 
A.cordata, supra xneo-picea, elongato-ovalis, depressa, subtilissime re- 
ticulata, thorace brevi, postice angustato, et lateribus sinuato, elytris thorace 
vix latioribus, postice non dilatatis ; subtus nigra, ore antennis pedibusque ru- 
bro-piceis. Long :45. 
Santa Fe, New Mexico. Mr. Fendler. Varies, with black feet ; the sides of the 
thorax are strongly rounded in front, and subsinuate behind; the base is as 
wide as the apex, the anterior dilatation being produced by the curvature of the 
sides; the anterior angles are acute, the posterior angles rectangular. The 
elytra are very little wider than the widest part of the thorax, regularly elongate, 
elliptical, with the usual series of punctures becoming irregular towards the tip. 
