On Aquatic Carnivorous Coleoptera or Dytiscide. 667 
elytra ; these can sometimes be seen, as is the case in Hydaticus capico!fa, 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 rugze much obliterated. 
From South America I have seen only females, but cannot observe any good 
character to distinguish them from the Madagascar and Mauritian individuals, 
Madagascar ; Mauritius; South America. 1004. 
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, pedibus 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 rugze 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 Raffray). 1003. 
1043. Hydaticus capicola, Aubé, M.C.—Elongato-ovalis, sat convexus, subtus 
piceus, prosterno anterius testaceo, supra rufo-testaceus, capite posterius nigro- 
signato, prothorace in medio plaga transversa nigra, elytris 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. 132, 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 middie feet. The female has 
some moderately coarse, short rugse 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. Il. 4R 
