On Aquatic Carmvorous Coleoptera or Dytiscida. 663 
1034, Hydaticus agaboides, n. sp.—Ovalis, posterius subrotundatus, nigro-piceus, 
capite prothoracisque lateribus testaceis, illo vertice plagaque inter oculos nigris, 
elytris fere omnino nigris, versus latera testaceis ibidemque nigro-irroratis, vel 
lineatis ; antennis pedibusque anterioribus testaceis, pedibus posterioribus piceis ; 
coxis posterioribus abdomineque rugulosis; tarsorum posticorum marginibus pos- 
terioribus breviter ciliatis. Long. 82, lat. 5 m.m. 
This species seems closely allied to the darker form of H. fabricu, it is however 
rather broader than it, and more rounded behind, the under surface, instead of 
being smooth, is corrugated in a peculiar manner, especially on the coxee and the 
basal ventral segments, there is a dark mark between the eyes, and the ciliz on 
the hind margins of the juints of the posterior tarsi are quite short. I have seen 
only one individual, which is a female, and has a few short rugose impressions near 
the sides of the thorax. This individual is much suffused with dark colour, and it 
is probable 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. 52 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 Indo- 
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 peninsula; 
+n 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 cilia 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 above 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 cilize of their 
hind margins are 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 
