ART. 19 EEVISION OF THE USECHINI — BLAISDELL. 3 



The tribal secondary sexual characters have heretofore been con- 

 sidered obscure. In the male the submentum bears a distinct spiculif- 

 erous puncture at middle near the base of the mentum; the spicule 

 s short, stout, and rigid. 



Genus USECHUS Motschulsky 



Usechus Motschulsky, Bull. Soc. Imp. Nat. Moscou, vol. 18, 1845, pt. 

 1, p.79. 



Form oblong-oval , moderately depressed . Eyes concealed in repose , 

 transverse, separated above by a distance about equal to three times 

 their greatest anteroposterior diameter, posterior border nearly 

 straight — very feebly arcuate, very slightly to somewhat distinctly 

 emarginate anteriorly behind the antennae, superior border rounded, 

 truncated below by the prominent obtusely angled lateral border of 

 the genae. The latter visible from above and slightly more promi- 

 nent laterally than the sides of the front before the eyes. Tempora 

 straight, parallel, and not more prominent than the eyes. Labrum 

 short and transverse. 



Antennae stout and gradually incrassate, short, joints closely artic- 

 ulated, basal joint shorter than the second and deeply seated in the 

 antennal fossa; last three joints dilated, slightly compressed, forming 

 a feebly differentiated and closely articulated 3-jointed club. Man- 

 dibles rather slender apically, deeply bifid, lobes acute, the superior 

 slightly longer. Antennal fossae not entirely visible from above, 

 but nearly hidden anteriorly by the horizontal sides of the pronotum. 



Scutellum minute, often apparently absent, when present slender, 

 entering but feebly between the elytra. Epipleurae flat in subhori- 

 zontal plane, rapidly broadening toward the base and more or less 

 distinctly defined by a rough subcariniform line of asperities toward 

 the humeri. Anterior coxal cavities more or less open behind. Tibial 

 spurs apparently obsolete (invisible). 



USECHUS LACERTA Motschulsky 



Plate 1, figures 5, 8, 9 



Usechus lacerta Motschulsky, Bull. Soc. Imp. Nat. Moscou, vol. 18, 1845, 

 pt. 1, p. 79, pi. 1, fig. 9. 



Form elongate-oval, roughly sculptured. Color black to piceous, 

 or paler according to degree of immaturity; luster dull to slightly 

 shining. Pubescence sparse, yellowish, hairs short and subsquami- 

 form, denser on the summits of the elytral tubercles. 



Head and mouth parts small, frontal suture obsolete, epistoma 

 truncate at apex, sides of the front strongly converging and slightly 

 arcuate from the feebly convex supra-antennal convexities, angles 

 moderately rounded. Front scarcely convex, impressed within the 

 sides; moderately coarsely and sparsely punctate above and beneath, 



