AMERICAN COLEOPTERA. 279 



TRIARTHRON Mserkel. 

 Head quadrangular, front eniarginate, clypeus membranous, labrum bilobed, 

 mandibles not prominent, dentate at middle of inner edge, eyes broadly oval, 

 transverse to the axis of the head ; beneath without antennal grooves, maxillary 

 palpi with the second joint moderate in length, third short, fourth nearly as 

 long as second, cylindrical, somewhat acuminate at tip. Antennae nearly as long 

 as the head and thorax, eleven-jointed, first joint short, stout, second half as 

 long, 3 — 8 gradually shorter and slightly broader, last three joints forming an 

 oblong mass the first two joints of which are broader than long, the last longer, 

 oval and acute at tip. Thorax transverse, feebly emarginate in front. Pro- 

 sternum short in front of the coxse, the cavities strongly angulate externally 

 and narrowly closed posteriorly. Middle coxse slightly separated, the raeso- 

 sternum oblique, not oarinate. Metasternum moderate in length, the side pieces 

 visible. Abdomen with six segments, the last small. Legs moderately robust, 

 femora canaliculate beneath, tibiae ciliate and feebly spinulose. Tarsi five- 

 jointed in both sexes, joints 1 — 4 gradually decreasing in length, fifth longer. 

 Tibial spurs stout, moderate in length. 



T. liCCOntei Horn. — Oblong-oval, ferruginous, moderately shining. Head 

 sparsely punctulate. Thorax twice as wide as long, apex feebly emarginate, 

 base arcuate, sides grailually arcuately narrowing from base to apex, hind 

 angles very obtuse, surface sparsely punctulate. Elytra a little wider than the 

 thorax, humeri obtuse, sides near base nearly straight, gradually narrowed at 

 apical third, disc with eight entire striae of moderately closely placed punctures, 

 the intervals flat, finely sparsely punctulate, the alternate intervals with dis- 

 tant coarser punctures. Body beneath punctate, sparsely pubescent. Length 

 .12— .14 inch; 3—3.5 mm. (PI. VI, fig. 15). 



Male. — Anterior and middle tarsi with the first four joints moderately dilated. 

 Posterior femora deeply canaliculate at apex, the outer edge serrulate its entire 

 length, the inner edge suddenly emarginate near the base and beyond the 

 emargination with three equal but not large teeth. (PI. VI, fig. 15 a). 



Female. — Tarsi slender. Posterior femora more slender than the male, simple 

 without serrations. 



Three specimens seen, two from Oregon and one from the high 

 Sierras east of Visalia, California. 



HYDNOBIIIS Schmidt. 

 Head short, eyes round, not prominent, clypeus small feebly emarginate at 

 middle or even slightly membranous. Labrum small usually deeply bilobed, 

 rarely broadly emarginate. Mandibles moderately prominent, toothed at the 

 middle of the inner edge. Maxillary palpi moderate in length, first joint very 

 short, second rather long, obconical, third half the length of the second, fourth 

 nearly as long as the preceding two. Antennae rarely passing the middle of 

 the thorax, eleven-jointed, first joint obconical, stout, second much shorter but 

 as stout, 3 — 6 gradually decreasing in length but becoming broader, joints 7 — 11 

 forming an abrupt elongate club nearly as long as the rest of the antenna, the 

 eighth joint smaller than the seventh or ninth ; antennae not received in grooves 

 on the under side of the head. Prosternum short in front of the coxse, the 

 coxae are conical-transverse, with trochantin, contiguous, the cavities angulate 

 externally and narrowly closed behind. Mesosternum oblique, moderately 

 separating the coxae, not carinate. Metasternum moderate in length its side 



