AMERICAN PHILOSOPHICAL SOCIETY. 511 



less dilated form, more gradually attenuated and more acute pos- 

 terior termination of the body. 



[A species of Agahus, afterwards described as A. infuscatus 



Aube : Culymhetes discolor Harris, is probably tbe same. — Lec] 



4. C. SERIATDS. — Black, immaculate, slightly purple-bronzed ; 



elytra with about three irregular series of punctures on each ; 



lateral edge of the thorax somewhat rectilinear. 



Length seven-twentieths of an inch. 



Body black; immaculate, above very slightly bronzed, divided 

 into very minute, suborbicular, depressed granules, beneath black ; 

 head, a transverse frontal puncture each side, with double, parallel, 

 obsolete, smaller ones above ; antennae and palpi rufous ; thorax, 

 submargin slightly depressed, dorsal line obsolete, lateral and basal 

 edges nearly rectilinear, posterior angles subacute ; elytra on each 

 three irregular series of villous punctures, and a submarginal less 

 distinct one; epipleura piceous; sternum acutely carinated, depres- 

 sed behind, slightly elevated, obtuse before ; feet rufous, posterior 

 pair piceous. 



This insect was sent me as distinct by Dr. J. F. Melsheimer. 

 It is very closely allied to C. nitidus, but is considerably larger. 



[Also an Agabus described as A. striatus Aube, and A. arvtux 



Mels.— Leg.] [98] 



5. C. NITIDUS. — Black; elytra with about three iiTegular series 



of punctures on each ; lateral edge of the thorax arquated each 



side. 



Length three-tenths of an inch. 

 Dytiscus tiitidus Melsh. Catal. 



Body black, immaculate, polished, and divided into very minute, 

 irregularly orbicular granules, beneath black ; head, a transverse, 

 abbreviated, frontal line each side, superior punctures obsolete or 

 wanting; antennas and palpi rufous; thorax, dorsal line abbre- 

 viated, central, lateral edge arquated, posterior angles subacute ; 

 elytra with three irregular series of villous punctures, and a sub- 

 marginal and sutural less distinct one ; epipleura black ; sternum 

 acutely carinated, depressed behind; feet piceous, anterior ones 

 rufous. 



The chief difference between this species and the preceding one 

 appears to rest in the general form and size of the body, the color 

 1823.] 



