228 MEMOIRS ON THE COLEOPTERA 



and almost smooth, the fourth distinct in basal third to nearly half, 

 disintegrated thence posteriorly, the fifth obsolete, though sometimes 

 more or less traceable apically, the sutural subentire, extending from 

 basal to apical fifth or sixth; humeral and subhumeral wholly wanting, the 

 oblique humeral long but very fine and feeble; inflexed sides nearly flat 

 but not sharply defined, having two striae, the outer fine, the inner broad 

 and shallow; propygidium even, rather strongly transverse, the punctures 

 small and extremely remote, very minute medially; pygidium smooth, 

 convex, minutely and very sparsely punctulate basally; prosternal lobe 

 obtusely rounded, unmargined; anterior tibiae with four teeth, the basal 

 minute, the distal very high, not evidently bifid. Length 3.8-4.2 mm.; 

 width 3.0-3.1 mm. Kansas (Salina). Three examples. 



The fine and extremely sparse punctures of the propygidium will 

 easily serve to identify this species; the mandibles are strongly 

 carinate and unusually punctate. 



Hister fluviatilis n. sp.- Somewhat less broadly oval than the preceding, 

 similar in color, lustre and subobsolete minute punctulation; head with 

 the frontal part of the ambient stria long, straight and entire; mandibles 

 less carinate and less punctate than in the preceding; prothorax just 

 visibly shorter than in lavicanda, though much less than twice as wide 

 as long, the sides much less converging from the base and subevenly, 

 feebly arcuate, the apical angles blunt and narrowly rounded; striae 

 nearly similar; elytra shorter than in the preceding but otherwise nearly 

 similar in outline and in the dorsal striation throughout; humerals want- 

 ing; inflexed sides with two rather broad shallow striae; pygidia narrower, 

 the propygidium with moderately strong punctures, separated by about 

 two or three times their diameters; pygidium only moderately convex, 

 very finely but deeply punctate throughout, more finely apically, slightly 

 more distinctly basally, the punctures everywhere rather sparse; pro- 

 sternal lobe obtusely rounded, not margined medially; anterior tibiae 

 quadridentate, the teeth short and broad, the basal minute, the distal 

 a little larger, narrowly and equally bifid. Length 3.8-4.0 mm.; width 

 2.75-2.85 mm. Missouri (St. Louis) and Mississippi (Vicksburg). 

 Five examples. 



This species seems to be peculiar to the Mississippi Valley in the 

 neighborhood of the great river; it is not to be confounded with any 

 other, except Icevicauda and nubilus, and, from the former, is easily 

 distinguished by its less broadly oval form, stronger, less sparse 

 pygidial sculpture, less converging and more arcuate sides of the 

 prothorax, less carinate or punctate mandibles and many other 

 characters. 



Nubilus Lee., is distinguished from the two preceding species, 

 which it much resembles, by the four entire dorsal striae and, from 

 Icevicauda in addition, by the much stronger and less sparse pygidial, 



