664 On Aquatic Carnivorous Coleoptera or Diftiscidce. 



considered distinct from it but their hind tarsi are not quite so stout, and have not 

 the cilise so largely developed. 



Besides these two extreme forms, a number of other less definite ones niaj be 

 distino-uished, 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, PhUippine Islands. 1010. 



1036. Hydaticus rhantoides, n. sp. — Ovalis, subtus rufescens, supi-a testaceus, 

 vertice nigro, elytris sequaliter nigro-irroratis ; tarsorum posticorum marginil)us 

 posteriori bus longissmie ciliatis. Long. lOi, lat. 5| m.m. 



In the male the fringing hairs of the front tarsi are rather well develoj^ed, and 

 the basal palettes ai'e 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 ciliae on the hind margins 

 of the joints of the posterior tai'si 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, Aub^, M.C. — Ovalis, s^jbtus rufescens, supra 

 testaceus, vertice nigro, elytris crebre nigro-irroratis, irrorationibus in maculam vel 

 fasciam discoidalem plus minusve discrete coalescentilius; tarsorum posticorum 

 marginibus posterioribus Lmgissime 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 antirely destitute of any sexual sculpture. 



This 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 ciliatiou 

 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. 



