300 GEO. II. HORN, M. D. 



entire surface rather coarsely punctate without traces of strial arrangeraent, 

 sides of elytra slightly sinuate. Legs rufo-piceous. Body beneath distinctly 

 alutaceous and sparsely punctate. Length .14 inch ; 3.5 mm. 



Male. — Anterior and middle tarsi dilated. Posterior femora slightly flattened 

 beneath not dentate. 



A very distinct species by the absence of aoy attempt at a atrial 

 arrangement of the punctures. 



One specimen, western Nevada. 



AGATHIDIUIVI IHig. 

 Head flat, quadrangular, received in the emarginate thorax as far as the 

 eyes, and with well defined oblique antennal grooves beneath. Clypeus either 

 slightly prolonged, continuous with the front or emarginate and partly 

 membranous. Labrum short, rounded in front. Mandibles simple, the left 

 sometimes prolonged or horned in the male. Maxillary palpi short, clavate, 

 the basal joint very slender, the terminal conical. Eyes oval, not prominent. 

 Antennse arising under a frontal margin, eleven-jointed, first joint stout, moder- 

 ate in length, second nearly as stout but shorter, third more slender and longer 

 (except dentigerum) than the second, joints 4 — 8 small, gradually broader, 9 — 11 

 forming an oblong, rather loose club. Anterior coxal cavities angulate exter- 

 nally, closed behind. Mesosternum variably separating the coxse and sub- 

 carinate or simple. Metasternum rather short the side pieces narrowly visible, 

 posterior coxse contiguous. Abdomen with six segments. Legs rather slender 

 but not long, tibise not spinulose externally, the spurs small. Tarsi slender and 

 varying between the sexes in the number of joints, being always 5 — 5 — 4 in 

 the males and 5 — 4 — 4 or 4 — 4 — 4 in the females. 



The clypeus presents several important modifications. In three 

 species {sexstriatum, histriatum and e&triatum), that member is en- 

 tirely corneous and distinctly prolonged beyond the sides of the front. 

 In concinnum and rotundulum the margin of front and clypeus is con- 

 tinuous without perceptible membranous border, and with membranous 

 border in exiguum, dentigerum, cah'fornicuin and revolvens. In onis- 

 coides, politum, pulchrum and dlfforme, the clypeus is broadly emargin- 

 ate and the emargination supplied with a membranous space. The last 

 three it will be observed have the left mandible larger in the male. 



These modifications of the structure of the clypeus from that form 

 in which the middle is prominent to that in which the middle is partly 

 membranous, unite in one genus all the important modifications which 

 are observed in the entire family, and indicate that they should not 

 be considered of any value in a generic point of view. 



Under polltum will be found some remarks on the latter character. 



The mesosternum has two important modifications which need no 

 further mention than that made in the synoptic table. 



A little variation occurs in the antennae in the length of the third 

 joint as well as in the size of the seventh which is sometimes a little 



