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

by Thomas Lincoln Casey

Nemota n. subgen.

The form is here rather stout, the elytra greatly developed, the middle coxæ slightly separated, the mesosternal process extending to their middle, the tip very acute, subaciculate and separated from the transverse and feebly, medially and obtusely cuspid metasternum, by a very long sunken acute ridge. The hind tarsi are slender, with the first three joints decreasing rather rapidly in length, the first much longer than the second, and the apices of the elytra are not definitely sinuate laterally. Male sexual marks are very feeble.

Atheta (Nemota) paganella n. sp.—Moderately stout and convex, rather shining, the abdomen with coarse reticulation posteriorly, obsolescent basally, the punctures throughout very fine, moderately close on the elytra, the pubescence not dense, rather coarse; body, legs and antennæ deep black throughout; head slightly transverse, parallel, the eyes prominent, at evidently more than their own length from the base, the rounded tempora barely perceptibly more laterally prominent, the carinæ obsolete except at the extreme base; antennæ rather thin, moderate in length, gradually feebly incrassate, the outer joints slightly transverse, the last rather stouter, gradually acutely pointed, fully as long as the two preceding, the second and third elongate, the former barely visibly the longer; prothorax rather small, moderately transverse, distinctly wider than the head and narrower than the elytra, slightly widest anteriorly, the sides moderately rounded, straighter basally, the basal impression distinct; elytra large, parallel, nearly as long as wide, very much longer as well as wider than the prothorax; abdomen narrower than the elytra, parallel but with the border narrowing gradually behind, the fifth tergite longer than the fourth; sixth ventral plate in the type prolonged behind, broad, circularly rounded at apex. Length 2.0 mm.; width 0.6 mm. California (Siskiyou Co.).

Recognizable by the deep black color of every part of the body and legs, the large subquadrate elytra and other characters as mentioned above.

Atheta (Nemota) filiola n. sp.—Similar in coloration, form and lustre, except that the body is not so stout and the legs not deep black, but blackish-piceous, the vestiture rather shorter and finer; head similar but relatively larger and except that the eyes are rather less prominent and at not at all more than their own length from the base, the tempora barely at all swollen; antennæ slender basally, but more distinctly and rapidly and evidently more strongly incrassate distally, the outer joints more transverse, the last a little smaller, the third evidently shorter than the second; prothorax nearly similar, convex, less evidently wider than the head and not quite so greatly narrower than the elytra, the sides more parallel and more rounded; elytra narrower and more nearly as long as wide, very much longer than the prothorax; abdomen distinctly narrower than the elytra, nearly similar, the hairs shorter, finer and more numerous, the tergites all a little shorter but similarly proportioned. Length 1.75 mm.; width 0.48 mm. California (San Bernardino Mts.),—Fall.

As stated in the description, this species, though allied rather closely to paganella, may be distinguished by its narrower form, shorter vestiture, more incrassate antennæ and other features.

Atheta (Nemota) timida n. sp.—Form, coloration, lustre and sculpture nearly as in filiola, the legs blackish-piceous; head nearly similar, parallel, the eyes rather convex, smaller, at much more than their own length from the base, the antennæ slender basally, gradually rather strongly incrassate distally, the outer joints slightly transverse, the ninth shorter than the tenth, the last rapidly pointed, as long as the two preceding, the second and third obconic, the latter the shorter; prothorax rather short and transverse, distinctly wider than the head and correspondingly narrower than the elytra, nearly parallel, with the sides subevenly and moderately arcuate, the basal impression distinct; elytra evidently shorter than wide, very much longer than the prothorax, not quite parallel; abdomen distinctly narrower than the elytra, parallel, the punctures fine, sparse, the hairs rather coarse; fifth tergite much longer than the fourth, the sixth ventral plate in the apparently male type produced behind, with the apex broadly and arcuately subtruncate. Length 1.8 mm.; width 0.48 mm. California (Sta. Cruz Mts.).

The sixth ventral of the male is more subtruncate at tip than in the broader and heavier paganella, and from filiola, it may be known by its longer antennæ, more prominent eyes and shorter and more transverse prothorax and elytra.

Atheta (Nemota) perpera n. sp.—Subparallel, rather convex, shining, black, the elytra dark piceous-brown, the legs pale, the punctures small, sparse, not dense and scarcely asperate on the elytra, the vestiture rather sparse and moderately coarse; head nearly as long as wide, slightly broadening basally, the eyes moderately convex, at fully their own length from the base, the carinæ obsolete; antennæ short, blackish, slender basally, the second and third joints elongate, subequal, the fourth a little longer than wide, thence gradually distinctly incrassate, the outer joints moderately transverse, the last fully as long as the two preceding; prothorax moderately transverse, much wider than the head but almost as wide as the elytral base, the parallel sides evenly and moderately arcuate, unimpressed; elytra subparallel, a little shorter than wide, much longer than the prothorax, the apices laterally feebly sinuate; abdomen nearly as wide as the elytra, parallel, narrowing just visibly apically, the fifth tergite longer than the fourth. Length 1.7 mm.; width 0.4 mm. California (Ojai),—Fall.

This species is aberrant in the tarsi, the basal joint of the posterior being elongate though scarcely so long as the second. The metasternum is transverse and does not project forward at all. The elytra are as transversely convex as the pronotum, the suture narrowly impressed at base.

Atheta (Nemota) perspecta n. sp.—Moderately slender and very feebly convex, shining though with obvious micro-reticulation, the punctures nearly as in the preceding, not close even on the elytra, the pubescence rather sparse, short; color pale brownish-testaceous, the head and abdomen piceous, the latter clouded blackish subposteriorly, the legs pale; head slightly transverse, the eyes prominent, a little shorter and less prominent than the slightly swollen tempora, the carinæ obsolete; antennæ dark, short though unusually slender, very feebly and gradually incrassate, the second and third joints elongate, the latter slightly the shorter, the outer joints narrowed basally as in the preceding, slightly transverse; prothorax moderately transverse, nearly as wide as the elytral base, distinctly wider than the head but less markedly so than in the preceding, the sides parallel and very moderately, evenly arcuate; elytra slightly shorter than wide, with feebly diverging sides, much longer than the prothorax, the apices not evidently sinuate laterally; abdomen almost as wide as the elytra, nearly as in the preceding. Length 1.7 mm.; width 0.36 mm. California.

The coloration will distinguish this species from any of the preceding and also the less incrassate antennæ; the sterna are as in the other species; the hind tarsi are missing in the type.