On Aquatic Carnivorous Coleoptera or Dijiiscidce. 335 



punctured, in fact almost impunctate ; the elytra have a rather coarse, but very- 

 little impressed and therefore obsolete punctuation ; the more internal of their 

 series of punctures can be distinguished at the base only, and the more external 

 series are extremely indistinct. 



The species is larger and broader than Hyphydrus rufo-niger, Clk. (Xo. 218), and 

 has the elytra more punctate, but with the inner series of punctures on the other hand 

 more indistinct. In form and sculpture it is nearer to Hydrovatus castaneus, 

 JVIotsch,, but it is larger and darker, and the margin of the clypeus is less obsolete. 

 It is the largest East Indian species here described. I have seen only a single 

 individual in bad condition ; it is I believe a female. 



Siam, (Bangkok), Castlenau. 1153. 



220. Hydrovatus bonvouloiri, n. sp. — Ferrugineus, latus, convexus, nitidus, pro- 

 thorace crebre punctato ; elytris fortiter sat crebre punctatis ; coxis parcius distincte 

 punctatis. Long. 3^, lat. 2^ m.m. 



Antennae rather long and slender, simple. Clypeus without margin, and very 

 slightly emarginate over the labrum. Head completely destitute of sculpture. 

 Thorax rather closely and somewhat finely punctured. Elytra with numerous 

 scattered, distinct punctures. Coxte very shining and with very distinct but 

 sparing punctures. 



India bor, (coll. Bonvouloir). 24. 



221. Hydrovatus major, n. sp. — Rufescens, supra piceo-rufus, capite, thorace, 

 elytrorum maculis dilutioribus ; elytris fortiter punctatis, anterius ad latera 

 impressione longitudinali profunda. Long. 3f, lat. 2j m.m. 



This species is of broad form ; the head has very little punctuation, but the 

 thorax is rather closely and distinctly punctured ; the elytra are strongly punctured, 

 the punctuation being very coarse and close near the sides, and obsolete at the apex, 

 a little behind the shoulder near the epipleura there is a deep elongate depression. 

 The posterior coxse are^very coarsely punctured. 



The species is remarkable by the impressions on the sides of the elytra ; the 

 colour of the upper surface is variable, and the red spots on the wing-cases are in 

 some instances much'more conspicuous than in others. The sexual ditierences seem to 

 be extremely slight , the antennae are slender and rather short, and in the male are 

 slightly more serrate internally than they are in the female ; and in this latter sex 

 the jDunctuation on the wing-cases seems to be just perceptibly denser than it is in 

 the male. 



It is closely allied to Hydrovatus horni, Crotch. 



Duenas, Guatemala, G. C. Champion, 1879. 1122. 



