On Aquatic Carnivorous Coleoptera or DytiscidcB. 667 



elytra ; these can sometimes be seen, as is the case in Hydaticus capicola, but when 

 the surface is very black can scarcely be traced. The serial punctures of the 

 elytra are usually less distinct than in H. capicola, but in one individual from Mada- 

 gascar they are as conspicuous as in the South African species : one female indivi- 

 dual from Dejean's collection has the thoracic ruga? much obliterated. 



From South America 1 have seen only females, but cannot observe any good 

 character to distinguish them from the Madagascar and Mauritian individuals. 



Madagascar; Maui-itius; Soxith America. lOOi. 



1042. Hydaticus galla, Guer., M.C. — Ovalis, sat latus et convexus, subtus piceus, 

 prosterno anterius testaceo, supra rufo-testaceus, capite posterius nigro-signato, pro- 

 thorace disco signaturis parvulis subconjunctis fuscis, eiytris crebre nigro-irroratis, 

 inter irrorationes lineis tribus vel quatuor vix conspicuis testaceis, antennis pedibus- 

 queanterioribus rufis, jiedibus posterioribus piceis ; elytrorum punctis seriatis parum 

 conspicuis. Long. 12^-, lat. 7 m.m. 



This species appears very closely allied to Hydaticus capicola, but is of less 

 elongate form, the black irrorations on the elytra are less dense, the mark on the 

 middle of the thorax is not a transverse line, but consists of some small closely 

 placed marks, somewhat of a hieroglyphic appearance, the middle and hinder legs 

 are shorter and stouter, and the female has no impressed rugse on the thorax. 



I have seen only four individuals of the species ; one of them (in the collection 

 of the Genoa Museum) is a curious variety in which the black dots of the elytra 

 behind the middle are condensed to form an irregular indistinct black fascia, behind 

 which the black dots are more scanty so as to leave a pale fascia, behind that the 

 dots are again condensed, and are again more scanty at the apex. 



Abyssinia, (found by Ilaffray). 1003. 



1043. Hydaticus capicola, Aub^, M.C. — Elongato-ovalis, sat convexus, subtus 

 piceus, prosterno anterius testaceo, supra rufo-testaceus, capite posterius nigro- 

 signato, prothorace in medio plaga transversa nigra, eiytris crebrius nigro-irroratis, 

 inter irrorationes lineis tribus vel quatuor vix conspicuis testaceis, antennis pedi- 

 busque anterioribus rufis, pedibus posterioribus piceis ; elytrorum punctis seriatis 

 conspicuis. Long. I3h, lat. 74 m.m. 



This insect has a great resemblance to the species of Rhantus (such as Colymbetes 

 pulverosus. No. 924). The male has about twenty-two palettes on the undersur- 

 face of the front tarsi, and about sixteen on the middle feet. The female has 

 some moderately coarse, short ruga? or impressions, about the sides of the thorax. 



The species varies somewhat in size, and in the denseness of the black irrora- 

 tions on the wing-cases, these, however, show very little tendency to the formation 



TRANS ROY. DUB, SOC, N.S., VOL. II. 4 R 



