AS [FeBRuary, 
IsaARTHRUS. 
Antenne tenues, extus paulo incrassate, articulis cylindricis, 2—12 subzequa- 
libus, 11™0 paulo longiore. (Palpi invisi.) Thorax subtus ad marginem pro- 
funde sulcatus: coxarum posticarum lamine tectrices intus modice dilatate, ad 
apicem late rotundate; tarsi tenues, articulo.1mo elongate, 2—4 gradatim bre- 
vioribus, 4t° vix dilatato. 
This genus differs from Fornax, by the third joint of the antenne being not 
larger than the 2d or 4th; and by the posterior coxal plates being less dilated in- 
teriorly, and much more broadly rounded at apex: the fourth tarsal joint is less 
dilated. 
1.1. spretus, elongatus utrinque obtusus, ater, breviter cinereo- pubescens, 
confertim subconfluenter punctatus, thorace convexo, antrorsum angustato, et 
rotundato, elytris striis tenuibus, interstitiis rugose punctatis, subconvexis, an- 
tennis pedibusque rufis. Long.:2. Lake Superior. Thisis the Fornaz spretus 
of my catalogue in Agassiz’ Lake Superior. 
Evcnemis Ahr. 
a. Antenne serrate: tarst articulo 4t0 simplici. 
1. E. clypeatus Say, Trans. Am. Phil. Soc. 6, 189: later clypeatus 
Say, Ann. Lyc. 1, 266. Pennsylvania, Zimmerman. 
b. Antenne serrate: tarsi articulo 4to breviter lobato. 
2. E. amewnicornis Say, Trans. Am. Phil. Soc. 6,189. Southern and 
Middle States. The antenne are subflabellate in both sexes: some specimens 
have the thorax a little rounded on the sides: these are probably females: the 
whole appearance is so similar to that of genuine Eucnemis, that I have not ven- 
tured to establish a separate genus upon the slight difference in the antenne and 
tarsi. 
Microruacus Esch. 
1. M. imperfect us, elongatus, utrinque obtusus, ater pubescens, puncta- 
tus, capite canaliculato, thorace Jatitudine breviore, lateribus antice rotundatis, 
elytris tenuiter striatis,pedibus rufo-piceis, sulcis pectoralibus postice indistinctis. 
Long. :22. New York, one female. 
2. M. subsinuatus, elongatus vix cuneiformis, ater, supra obsolete pubes- 
cens, punctatus, thorace brevi, antrorsum subangustato, lateribus subsinuatis, 
angulis posticis explanatis, elytris rugose punctatis, obsolete striatis, tarsis tes- 
taceis. Long. :2. Georgia, one male; similar to the next, but more than twiceas 
large, and easily distinguished by the sinuosity of the sides of the thorax: it is 
also more coarsely punctured and less narrowed behind. 
3. M. triangularis. Elater triangularis Say, Journ. Ac. Nat. Sc. 3, 170: 
Euenemis triangularis Say, Trans. Am. Phil. Soc. 6, 189. Southern and West- 
ern States: the thorax is not at all narrowed in front; the anterior angles are a 
little rounded. It is singular that Guérin, (Ann. Ent. Soc. Fr. 1, 187,) should 
refer this species to Eucnemis, when Say expressly states the antennal groove to 
be near the middle of the pectus. 
4. M. humeralis. Eucnemis humeralis, Say, Trans. Am. Phil. Soc. 6, 
189. Pennsylvania, Dr. Melsheimer. 
Gaxuea Esch. 
1.G.(Dendrocharis) flavicornis Guérin. Ann. Ent. Soc. Fr. 2dser. 
1, 193. tab. 6, fig. 60, 61. Georgia; I have never seen this fine species. 
The following species are unknown to me, and the genera to which they be- 
long doubtful. 
EKuecnemis quadricollis Say, Trans. Am. Phil. Soc. 6,186. Pro- 
bably Melasis. 
Fucnemis frontosus Say, ibid. Probably not of this group. 
Euenemis calceatus Say,ibid. The descriptionof the antenne agree 
perfectly with my Isarthrus spretus; but the 4th joint of the tarsi in that species 
is not lobed beneath. 
