On Aquatic Carnivorous Coleoptera or Dytiscidce. 741 



entirely cover them at the base, behind the base leave a narrow space along the 

 suture smooth, and at the apex leave about one-sixth of the length uncovered : the 

 epipleurse are flattened and oblique, but this torsion does not extend farther back 

 than the first ventral segment. 



The species varies a good deal in size and especially in width, but is easily discri- 

 minated from the preceding one, by the colour of the front and middle femora ; 

 the wing-cases of the males generally bear excessively fine tubercles, with rudiments 

 of transverse aoiculations between them, thus showing a slight development of the 

 sculpture which becomes so remarkable in C. rugosus. 



Aube's description of the female of C. guerini was probably taken from another 

 species, for he states that it has very little sexual sculpture, I have seen only a 

 single example agreeing with this statement, and think it very probably a distinct 

 species. 



Mantcliuria, China, Siam, Laos, Java, Celebes. 1089. 



1159. Cybister bengalensis, Aube, Trogus hengalensis, M.C — Ovalis, supra 

 olivaceus, capite anterius prothoraceque ad latera testaceis, elytris vitta intra- 

 marginali, apice hamato-dilatata, suturam haud attingente, testacea ; corpore 

 subtus variegato, ex parte majore nigro, pectore utrinque late testaceo, abdomine 

 nigro, segmento basali plaga laterali testacea, segmentis 3 — 5 testaceo-maculatis ; 

 pedibus quatuor anterioribus testaceis, tarsis intermediis pedibusque posterioribus 

 nigricantibus, his femoribus apice rufo ; elytris extrorsum versus apicem subtiliter 

 sed perspicue coriaceo-rugulosis. Long. 292, lat. 16 m.m. 



The front tarsi of the male attain scarcely 3 m.m. in the transverse direction ; 

 the intermediate feet have rather large patches of sexual pubescence on the two 

 basal joints and generally an obscure narrow patch on the following joint. The 

 female has no trace of any sexual sculpture, and the epipleurse are quite simple as 

 in the male. 



The species seems to vary but little ; I have seen only one specimen stated to be 

 from India, and I consider it doubtful whether it occurs there. 



I have little doubt, from individuals before me, that other species with a similar 

 colour of the undersurface exist, differing, however, in the sexual characters. As 

 regards the name of the species, this is the only one to which Aube's description is 

 applicable ; but as far as I know it is found only in China, but the French author 

 says it occurs " aux Indes crientales et en Chine " ; it is possible, therefore, that his 

 description was made from Chinese examples, and the epithet " bengalensis " was 

 used for the species because individuals from Bengal were supposed to be con- 

 specific. 



Chiuii ; especially towards the North. (Sechuan, A. Da-vid.) 1090. 



5 C 2 



