The Pselaphid/E of North America. 243 



and one-half wider than the head, widest behind the anterior 

 third where the sides are acutely rounded and toward the 

 neck and the base nearly straight; disk moderately convex, 

 near the base with an angulated transverse sulcus, ending on 

 the sides in an ample impression, containing a small fovea. 

 Elytra across the shoulders as wide as the prothorax, widest 

 behind the middle, where it is one-half wider and along the 

 suture one-third longer than the shoulder-width; disk rather 

 depressed near the base, sutural lines slightly impressed, basal 

 foveje small, the sutural ones near a transverse elevation of 

 the base, the discal ones in the anterior part of a shallow 

 oblong depression, below the humeral ridge a fovea con- 

 nected by an oblique line with the lateral margin. Abdomen 

 as wide as the elytra, slightly convex, without the basal 

 impressions, segments subequal, border narrow. The pubes- 

 cence of the elytra and the dorsal segment arranged in regu- 

 lar rows. Anterior cox^e contiguous, posterior ones distant, 

 trochanters short triangular, legs slender, anterior femora 

 crenate below, tarsi with one claw, second joint twice as long 

 as the third, metasternum not impressed. 5 anterior tibiae 

 arcuate with a deep notch inside on the distal fourth of its 

 length, clypeus with a medial ridge. ? tibiae and clypeus 

 simple. 



Habitat. Alameda county, California. 



This singular insect unites some of the characters of 

 Bythinns [Machcerodes) carinatus and Pselafhus loiigipalpiis, 

 the antennas and the palpi belonging to the European 

 Machcvrites group of the Bythini, the form of the head 

 approaching that of Psclaphns. According to the testimony 

 of Dr. David Sharp, there is no genus known, with which it 

 can be united. 



PsELAPHUs, Bbsi. [i>?,/.ni,dio, I feel my way — referring to the 



very long maxillary palpi.) 



Head longer than broad, eyes large, prominent. Prothorax 



as long as the head, barrel-shaped, polished, nearly twice as 



long as thick. Elytra conjointly forming nearly an equilateral 



