242 MEMOIRS ON THE COLEOPTERA 



long as wide; prothorax short, slightly widest behind the middle, not 

 wider than the elytra, moderately narrowed anteriorly, the sides rather 

 strongly arcuate, the basal angles slightly obtuse but distinct and 

 slightly flexed posteriorly; elytra short though relatively longer than in 

 impellens, the suture four-fifths as long as the prothorax, the apical 

 sinuses distinct; abdomen rather slender, at base distinctly narrower 

 than the elytra, rather rapidly and evenly tapering though less strongly 

 so than in the preceding, the fifth tergite nearly two-thirds as wide as 

 the base, the sixth dorsal and ventral plates obtusely rounded in the 

 type, the ventral with minute serrules at tip. Length 1.4 mm.; width 

 0.42 mm. California (Paraiso Hot Springs, Monterey Co.). 



This species is rather closely allied to impellens but has the elytra 

 relatively less abbreviated and. the abdomen less tapering. 



Myllsena frivola n. sp. Somewhat slender and only moderately 

 convex, piceous-black throughout, the legs paler; surface feebly shining, 

 the elytra opaque, the vestiture dark, moderately short, dense, the 

 minute imbricate sculpture of the abdomen distinct to the apex; head 

 relatively large, nearly two-thirds as wide as the prothorax, the an- 

 tennse (cf) piceous, paler basally, rather long though feebly incrassate 

 distally, the tenth joint slightly longer than wide; prothorax rather short, 

 three-fifths wider than long, unusually slightly narrowed at apex, the 

 sides parallel and feebly arcuate, rounding anteriorly, equal in width to 

 the elytra, the basal angles slightly obtuse, feebly prominent posteriorly; 

 elytra equal in length to the prothorax, the apical sinuses distinct; ab- 

 domen rather slender, at base not as wide as the elytra, gradually and 

 evenly tapering, the fifth tergite nearly three-fifths as wide as the base, 

 the sixth ventral plate circularly rounded and with a loose fringe of 

 short stiff setae at apex. Length (extended) 1.75-1.85 mm.; width 

 0.45-0.5 mm. Nevada (Elko), Wickham. 



Distinct in its feebly convex form, dark coloration, equal length 

 of the prothorax and elytra and in antennal structure. 



Myllaena esuriens n. sp. Rather slender and very moderately convex, 

 dull, the minute punctures everywhere very dense, the imbriform reticu- 

 lation of the abdomen minute and very close, with the hairs very fine 

 and close and evenly, longitudinally decumbent; color piceous-black 

 throughout, the legs pale; head nearly three-fifths as wide as the pro- 

 thorax, the antennae (cf ) dark, paler basally, not very slender, feebly 

 incrassate distally, the tenth joint a fourth longer than wide; prothorax 

 well developed though strongly transverse, fully three-fifths wider than 

 long, slightly widest a little before the base, where the sides are moder- 

 ately rounded, thence not very strongly convergent and straighter to 

 the apex, the base rather strongly, evenly arcuate, not appreciably sinuate 

 laterally, the basal angles distinct but obtuse; elytra at base a little 

 narrower, at apex equal in width to, the prothorax, the suture equal in 

 length to the latter or even somewhat longer, the apical sinuses large 

 and deep; abdomen evenly tapering, at base not quite so wide as the 



