138 Memoirs on the Coleoptera 



The inner margin of the epipleura is angulate as in californicus. 

 The general character of the sculpture much more closely resembles 

 that of californicus than riparius, where the pronotal surface is 

 much more even, and the small darker convexity at the centre of 

 the elytral foveolae much smaller; there is no trace of the strigilate 

 patch at the centre of the front in riparius and barely any trace of 

 it in californicus. 



The following species also belongs to this riparius section of the 

 genus, but differs greatly in its relatively broader form and sharply 

 angulate humeri: 



Elaphrus hesperius n. sp. — Form more abbreviated than in riparius, 

 californicus or finitimus, with especially shorter hind body, paler and 

 subcupreous-brown in color, dull in lustre, the few elevations of the 

 elytra, which are disposed as in the preceding, polished black; foveolae 

 large, rather shallow, annulate and greenish, with the central umbo very 

 large, feebly convex and more obscure in color; entire upper surface 

 finely and very densely punctured; under surface greenish-aeneous, less 

 finely and less densely punctured than the upper surface, the abdomen 

 smooth medially; legs as in the preceding; head as in finitimus, except 

 that the central feeble convexity never has more than a trace of strigila- 

 tion; antennae rather short and thick, the three smooth basal joints 

 feebly metallic; prothorax a fifth wider than long — sometimes fully a 

 fourth, the general outline as in finitimus, the surface more densely 

 punctate, less uneven, the sublateral pit being wholly obsolete, and 

 having about three small rounded areas at each side, in which the color 

 is dull steel-blue; median line tumid at apex and base, striate at the 

 middle, the divaricate impression obtuse; elytra but little over a fourth 

 longer than wide, widest, slightly inflated and not quite twice as wide 

 as the prothorax at about the middle, gradually but very obtusely 

 rounded behind; humeral angles very obtuse but sharply defined, the 

 sinus near basal fourth deep, rounded and conspicuous. Length (cf 9 ) 

 6.2-7.0 mm.; width 3.15-3.4 mm. California (Humboldt to S. L. 

 Obispo Co.). Eleven specimens. 



I believe that both sexes are represented in the series at hand, 

 but scarcely any sexual differences in structure are visible, the 

 anterior tarsi of the male are a little shorter than in the female but 

 only just visibly less slender. In the eastern ruscarius Say, which 

 belongs to this section of the genus, the prothorax is distinctly 

 narrower than the head, and the irregularities of the elytral surface 

 are more effaced, the sinus behind the humeri distinct and the 

 humeral angles rounded; the tibiae are paler in color; lecontei Cr. 

 (intermedius || Lee), from Utah, also belongs to this section of the 



