Casey — Observations on the Staphylinidae. 381 



ters Niidobius is somewhat intermediate between Eulissus and 

 allied genera and JCantholinus, but in the rapid medial de- 

 flection of the side margins of the prothorax, which unite 

 with the lower margin and do not continue separate there- 

 from to the apex, it is wholly isolated. The integuments are 

 highly polished throughout, but the surface of the head and 

 pronotum has, besides the normal punctures, a system of very 

 minute sparse punctules, evenly distributed throughout, and 

 these surfaces have besides a ver}'- feeble and frequently obso- 

 lescent minute transverse wavy strigilation. The species in 

 my cabinet may be described as follows : — 



Head behind the line of the antennae about as long as wide 2 



Head behind the antennae longer than wide 8 



2 — Species of the Atlantic regions. Body snaall in size, rather slender, 

 moderately depressed, black, the pale elytra clouded with piceous-black 

 posteriorly and externally; legs pale rufous, the antennae piceous, ru- 

 fous toward base; head rather coarsely, very sparsely punctured even 

 toward the sides; antennae much longer than the head; prothorax 

 slightly narrower than the head, a fourth longer than wide, the sides 

 strongly converging posteriorly from a short distance behind the an- 

 terior angles to the base, the punctures very fine as usual; elytra dis- 

 tinctly longer than wide, a little wider than the prothorax, and, on the 

 suture, about as long, narrower than the head, sparsely punctured, the 

 punctures feebly sublineate on parts of the disk but wholly wanting in a 

 polished convex line at the summit of the deflexed flanks as usual; ab- 

 domen minutely, very remotely punctate. Length 6.5 mm.; width 0.9 

 mm. Massachusetts and Virginia to Lake Superior; Ohio (Cincinnati). 

 {== astimilis Kirby, consentaneus and ^awipenfiis Nordm., kiesenwetteri 



Sachse aud palliatxis Mels.] cephalas Say 



Species of the Sonoran regions 3 



Species of the true Pacific coast fauna 5 



8 — Elytra large, much longer as well as wider tban the prothorax. Body 

 much stouter than in cephalus, black as usual, the elytra piceous-black, 

 obliquely pale in nearly basal half; legs dark ferruginous, the antennae 

 piceous-black, becoming rufo- piceous toward base, stouter distally than 

 in cephalus; head rattier coarsely, very sparsely punctate, the punctures 

 less sparse toward the eyes, the front with a small impression between 

 the posterior ends of the frontal grooves; prothorax much narrower 

 than the head, a fifth longer than wide, smaller than usual in the genus, 

 the sides as strongly convergent as in cephalus; elytra longer than wide, 

 a fourth longer and wider than the prothorax but not quite as wide aa 

 the head, sparsely and rather confusedly punctured; abdomen very 

 sparsely punctulate. Length 7.2 mm.; width 1.1 mm. Utah (south- 

 western ) nnbipennls n. sp. 



Elytra relatively smaller, equal in length to the prothorax and only slightly 

 wider, the body black throughout, with rufous legs and piceous-black 



