Memoirs on the Coleoptera/Volume 1/New Species of the Staphylinid Tribe Myrmedoniini/Tribe Myrmidoniini/Group Athetæ/Atheta/Athetalia

by Thomas Lincoln Casey

Athetalia n. subgen.

This subgenus differs from Anepsiola in having the infra-lateral carinæ of the head very strongly developed and entire; the abdomen is narrower and is not always parallel. The middle coxæ are contiguous, the mesosternal process acutely angular or prolonged and aciculate, and the metasternal extremely short, very broadly angulate. One of its most salient characters is the very long basal joint of the hind tarsi, so unusual a character in Atheta, this joint being fully as long as the next two combined throughout. The three species at present assignable are as follows:

Atheta (Athetalia) bicarinceps n. sp.—Rather stout and convex, shining, fusoid, testaceous, the head slightly darker, the abdomen, except apically, black; legs pale, the antennæ infuscate; head parallel at the sides, the eyes rather prominent, at their own length from the base; antennæ long, gradually incrassate, the outer joints not quite as long as wide, the eleventh pointed, not quite as long as the two preceding; prothorax convex, transverse, one-half wider than the head, the sides parallel and broadly rounded, the minute punctures sparse, the basal impression well developed; elytra wider than long, the suture much longer than the prothorax, the punctulation only moderately close-set, the micro-reticulation rather feeble; abdomen at base evidently not so wide as the elytra, thence evenly tapering to the tip of the fifth tergite, where it is three-fourths as wide as at base, the tergites flat, the basal impressions fine, the punctulation feeble and sparse, the sixth rounded, becoming gradually sinuate medially at tip, the sixth ventral rather than narrow and acutely angular, the apex of the angle slightly blunted; mesosternal process long and acicular; basal joint of the hind tarsi very long, fully as long as the next two. Length 2.8 mm.; width 0.73 mm. California (Siskiyou Co.).

The tapering form of the abdomen is remarkably exceptional in the true Athetæ and this character alone will serve to isolate this species from its fellows; the infra-lateral carinæ are very strong and are entire.

Atheta (Athetalia) repensa n. sp.—Moderately stout, more parallel, rather convex, shining, colored as in the preceding, the elytra however in the type having feeble infumation apico-externally and medio-basally; integuments polished between the punctures, without the usual micro-reticulation; head nearly as in the preceding but relatively larger, the eyes not quite so convex; antennæ a little more rapidly and strongly incrassate distally but otherwise nearly similar; prothorax not quite so large, slightly narrower than the elytra and distinctly but not so greatly wider than the head as in bicariniceps, otherwise similar, except that there is no basal impression, and, instead, a fine even impressed line throughout the length; elytra slightly transverse, much less so than in the preceding and very much longer than the prothorax, finely, closely, simply and very clearly punctate; abdomen parallel or very nearly, slightly narrower than the elytra; basal joint of the hind tarsi similarly long, the mesosternal process very much shorter and triangular, not prolonged and finely aciculate as it is in the preceding. Length 3.3 mm.; width 0.75 mm. California (Sta. Cruz Mts.)

Very distinct from bicariniceps in the formation of the sterna and abdomen; the infra-lateral carinæ of the head are similarly entire but are finer and not so elevated.

Atheta (Athetalia) nimia n. sp.—Form parallel, convex, large in size, black, the elytra, legs and antennæ basally brownish-rufous, the abdominal tip faintly paler; lustre moderately shining, the integuments rather strongly micro-reticulate, the abdomen with excessively fine and close transverse strigulation; head well developed, the eyes not very convex, at about their own length from the base; antennæ not quite so long, moderately stout, not gradually incrassate but parallel except basally, the joints slightly wider than long, the eleventh not quite so long as the two preceding; prothorax distinctly wider than the head and correspondingly narrower than the elytra, convex, transverse, parallel, unusually strongly and evenly rounded at the sides, finely, not densely punctulate and with two minute approximate and coalescent impressions before the base; elytra large, wider than long, finely punctulate, very much longer as well as wider than the prothorax; abdomen parallel, much narrower than the elytra, minutely, sparsely punctulate, the fifth tergite a little longer than the fourth, the sixth in the type broadly rounded, becoming gradually distinctly sinuate at the middle of the apex; mesosternal process very long, extending three-fourths of the coxal length, becoming very finely drawn out and aciculate. Length 4.2 mm.; width 1.0 mm. British Columbia (Metlakatla),—Keen.

This is the largest Athetid known to me from North America and is very distinct from the two preceding. The basal joint of the hind tarsi is similarly elongate.