Staphylinidæ.
47
|
the depressed intermediate ridge rather convex; hind tarsi somewhat elongate, with the first four joints subequal. Length 1.8 mm.; width 0.45 mm. New York (Ithaca). |
Readily distinguishable by the form of the head and antennal characters.
| Atheta (Traumœcia) orbiceps n. sp.—A little larger than the preceding, still more blackish throughout, the elytra very dark piceous-brown, the legs pale, the antennæ as in ithacana dark piceous, paler basally; pubescence a little longer; head slightly smaller, more orbicular, but slightly wider than long, the tempora behind the large eyes converging and more rounded to the base; carinæ similar, the antennæ nearly similar, the outer joints only very moderately transverse, nearly as in ithacana but relatively somewhat larger, much wider than the head, not impressed along the median line; elytra similarly slightly wider and much longer than the prothorax, scarcely more distinctly wider than long and subparallel; abdomen longer, more parallel, not narrowed apically, the sides nearly straight, the fifth tergite much longer than the fourth, the sixth as in the preceding but broader; sterna as in ithacana, the obtusely angulate metasternal projection somewhat blunter, the tarsi similar. Length 2.1 mm.; width 0.45 mm. Iowa (Cedar Rapids),—Brendel. |
Closely allied to the preceding but differing in the form and size of the head, smaller terminal joint of the antennæ, more parallel abdomen and other features.
| Atheta (Traumœcia) subdola n. sp.—General form, coloration and sculpture as in the preceding but more slender and with a notably smaller prothorax, rather more shining; head and antennæ similar; prothorax moderately transverse, parallel but more strongly rounded at the sides, very moderately wider than the head though much narrower than the elytra, very obsoletely impressed along the median line; elytra but little wider than long, very much longer than the prothorax; abdomen as in orbiceps; sterna similar, the mesosternal process not quite so finely pointed and the metasternal projection rather more sharply angulate; hind tarsi similarly slender, with the first four joints equal. Length 2.0 mm.; width 0.42 mm. Wisconsin (Bayfield),—Wickham. |
In general organization the three preceding species agree very well, and they form a perfectly natural group, whether or not actually the same as the European Traumœcia, as represented by a specimen before me named T. ravilla Er.
The following species is aberrant in its more strongly asperate sculpture:
| Atheta (Traumœcia) asperiola n. sp.—Subparallel, very moderately convex, scarcely shining, distinctly micro-reticulate, the punctures fine and close, strongly asperulate, the vestiture short; dark piceous, the head and abdomen |
