On Aquatic Carnivorous Coleoptera or Dytiscide. 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 
epipleure 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, bv the colour of the front ‘and middle femora ; 
the wing-cases of the males generally bear excessively fine tubercles, with rudiments 
of transverse aciculations 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. 
Mantchuria, China, Siam, Laos, Java, Celebes. 1089. 
1159. Cybister bengalensis, Aubé, Trogus bengalensis, 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 utringue late testaceo, abdomine 
nigro, segmento basali plaga laterali testacea, segmentis 8—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, 293, 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 epipleurze 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 Aubé’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 orientales 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. 
China ; especially towards the North. (Sechuan, A. David.) 1090. 
