On Aquatic Carnivorous Coleoptera or Dytiscidoe. 663 



1034. Hydaticus agaboides, n. sp. — Ovalis, posterius subrotundatus, nigro-piceus, 

 ■capite prothoracisque lateribus testaceis, illo vurtice plagaque inter oculos nigris, 

 elytris fere omnino nigris, versus latera testaceis ibidemque iiigro-irroratis, vel 

 lineatis ; anteniiis pedibusque anterioribus testaceis, jjedilius posterioribus piceis ; 

 coxis posterioribus abdomineque rugulosis ; tarsorum posticorum uiarginibus pos 

 terioribus breviter ciliatis. Long. 82, lat. 5 m.m. 



This species seems closely allied to the darker form of H. fabricii, it is however 

 rather broader than it, and more rounded behind, the under surface, instead of 

 buiug smooth, is corrugated in a peculiar manner, especially on the coxo3 and the 

 l)asal ventral segments, there is a dark mark between the eyes, and the ciliae on 

 the hind margins of the joints of the posterior tarsi are quite short. I have seen 

 only one individual, which is a female, and has a few sln)rt rugose impressions near 

 the sides of the thorax. This individual is much suffused with dark colour, and it 

 is pi'obable that in other individuals, the testaceous colour may be less concealed 

 than in it. 



Cochin China. 1011. 



1035. Hydaticus fabricii, Macleay, Ann. Jav. p. 134. — Species variabilis; minor, 

 ovalis, parum convexus, subtus rufescens,plus minusve nigricans, supra rufo-testaceus, 

 vertice nigro, elytris creberrime nigro-irroratis, irrorationibus versus suturam plus 

 minusve coalescentibus ; tarsorum posticorum marginibus posterioribus sat longe 

 ciliatis. Long. 10, lat. b\ m.m. 



In the male the fringing hairs round the heel of the front tarsus are short, and 

 the basal palettes are only a little larger than the others ; the female has generally 

 a. few short impressions on each side of the thorax. 



This species is very common in collections, and is widely distributed in the Izido- 

 Malay region, and is very variable, the variations being to a large extent determined 

 by the geographical habitat. The most distinct form occurs in the Malay jjeninsula; 

 in it the outline is rather narrow and parallel, the colour very dark, owing to the 

 predominance of the black spots causing the sutural region of the wing-cases to be 

 largely quite black, the thorax is generally a little blackened at the base in the middle ; 

 the fringing hairs of the male front tarsi are quite short, the posterior tarsi are rather 

 slender, and the cilige of the hind margins of the joints occupy a comparatively 

 small portion of the surface. 



In the continent of India and Ceylon a form differing much from the abu\c is 

 found, it is rather larger and broader, the black dots of the elytra are evenly distri- 

 buted and not confluent, the hind tarsi are shorter and stouter and the cilia; of their 

 hind margins ar^ longer and occupy a larger portion of their surface ; the extreme 

 individuals of this form are very similar to H. rhantoides, and are scarcely to be 



