664 On Aquatic Carnivorous Coleoptera or Dytiscida. 
considered distinct from it but their hind tarsi are not quite so stout, and have not 
the cilize so largely developed. 
Besides these two extreme forms, a number of other less definite ones may be 
distinguished, the above mentioned characters varying in degree of development 
and the manner in which they are combined; the specimens from the Philippine 
Islands, Celebes, and the Andaman Islands, approach more or less closely to the 
Australian H. consanguineus. 
India, (Deccan) ; Ceylon, China, Penang, Malacca, Bangkok, Borneo, Sumatra, Andaman Islands, Java, 
Celebes, Philippine Islands. 1010, 
1036. Hydaticus rhantoides, n. sp.—Ovalis, subtus rufescens, supra testaceus, 
vertice nigro, elytris sequaliter nigro-irroratis ; tarsorum posticorum marginibus 
posterioribus longissime ciliatis. Long. 102, lat. 54 m.m. 
In the male the fringing hairs of the front tarsi are rather well developed, and 
the basal palettes are distinctly larger than the others ; the female is almost entirely 
destitute of any sexual sculpture. 
This species is remarkably similar in size, form and colour to Dytiscus exoletus 
(Rhantus, No. 951), from which however a glance at the ciliz on the hind margins 
of the joints of the posterior tarsi will distinguish it. It is very closely allied to H. 
consanguineus, but it is usually rather smaller, of rather more rounded form, the 
black dots on the elytra are evenly distributed and not all confluent, and the fring- 
ing hairs of the male front tarsi are not quite so highly developed. 
Japan, Formosa, Mantchuria, China. 
1037. Hydaticus consanguineus, Aubé, M.C.—Ovalis, subtus rufescens, supra 
testaceus, vertice nigro, elytris crebre nigro-irroratis, irrorationibus in maculam vel 
fasciam discoidalem plus minusve discrete coalescentibus; tarsoram posticorum 
marginibus posterioribus longissime ciliatis. Long. 11, lat. 6 m.m. 
In the male the fringing hairs of the front tarsi are highly developed and con- 
spicuous, and the two basal palettes are quite distinctly larger than any of the others; 
the female is almost entirely destitute of any sexual sculpture. 
Tbis species is slightly different in form from the allies, its greatest width being 
distinctly behind the middle of the wing cases. ‘The tendency for the black dots of 
the wing cases to coalesce into a discoidal black mark may always be perceived, 
though in some cases it is very much more evident than in others. The ciliation 
of the posterior borders of the joints of the hind tarsi attains a great development, 
and the anterior limit of the ciliate portion of each joint is extremely arched. 
Australia and New Caledonia; apparently abundant. 1008. 
