On Aquatic Carnivorous Coleoptera or Dytiscidce. 71 7 



Group 2. 



1122. Cybister sugillatus, Er., Trogus bisi^natus, M.C — Ovalis, parum latus, supra 

 olivaceo-niger, prothoracis lateribus plus minusve obsolete rufescentibus, subtus 

 niger, pedibus nigris, plus minusve rufo-variis, tibiis posterioribus superne versus 

 geniculam plus minusve rufescentibus ; antennis rufis, extrorsum fuscescentibus. 

 Long. 22, lat. 12 m.m. 



Ill the male of this species the front tarsi are comparatively small, and the pub- 

 escent area on the undersurface of the basal joint is quite small ; the longitudinal 

 band of sexual pubescence on the undersurface of the basal joint of the middle tarsi 

 is so little developed that it easily escapes detection, and consists only of a few 

 short pale setae. The female has no sexual sculpture ; the obsolete supplementary 

 claw of its hind foot is easily detected. 



The species varies a good deal in size and in other respects ; it is sometimes 

 peculiarly dull and its upper surface has then a greasy appearance, at other times 

 it is comparatively shining, and may even have a faint metallic tinge. The reddish 

 colour at the sides of the thorax can be sometimes scarcely perceived while at other 

 times it is very distinct ; there is often a dark red spot near the extremity of each 

 wing case, but sometimes it is quite absent : the colour of the legs also varies a 

 little : the intermediate and anterior femora are nearly black, but are reddish towards 

 their apex, and their trochanters are also red : there is a more or less obscure red- 

 dish spot on each side of the basal abdominal segments. Cybister notasicus, A ube, 

 and C. olivaceus, Boh., are pretty certainly merely synonyms of this species, which 

 is usually known in collections under the name of C. bisignatus, Aub^. 



China, Thibet, India, Malacca, Philippine Islands, Sumatra. 1053. 



1123. Cybister (Trogus) nigripes, Wehncke, Stet. Ent. Zeit. XXXVII, p. 358. — 

 Ovalis, sat latus, parum convexus, niger, elytris posterius subtiliter transversim 

 corrugatis, epipleuris posterius sat latis et planatis. Long. 21, lat. 12 m.m. 



I have seen but a single individual of this species, and it is in such very bad 

 condition that I cannot exactly determine its characters ; it differs from C. sugillatus, 

 by its much broader form, by the corrugate elytra and broader epipleurse ; from C. 

 siamensis it differs by its much smaller size and shorter form : it has probably the 

 same sexual characters as the two species alluded to, and it is probable that the 

 black colour of the legs is due to this being dyed by the complete rotting of the 

 interior of the specimen. 



Borneo. 1069. 



1124. Cybister siamensis, n. sp. — Ovalis, latus, anterius angustatus, niger, 

 pedibus anterior) bus et intermediis rufo-variis, antennis rufis extrorsum fuscescenti- 



•1 Z 2 



