species of Haliplida. and IlydroporidcB. 425 



a Hydroporus, and of a subsection which has representatives 

 nearly all over the world, the tarsi, by themselves, would almost 

 determine it to be a Hyphidrus : I have seen, on the other hand, 

 species of Hyphidri, which, if their position were decided by the 

 form of their tarsi, would perhaps be grouped among the Hydro- 

 pori. In Hydrocantharidce at least (and in other families also), it 

 is the general focies of an insect, although it may be difficult to 

 express this in the exact terms of a critical diagnosis, which is a 

 more truthful guide as to its natural position than either the joints 

 of the tarsi or the structure of the mouth or any single separate 

 organ, if considered by itself and without reference to the rest. 

 The species before us nearly resembles H. Malaccce ; without close 

 microscopic examination (which is absolutely necessary for the 

 determination of all these minute species), it would perhaps be 

 not easy to separate them ; the thorax (longitudinally and me- 

 dially) is deeper ; that is, the angle of its base at the scutellary 

 region is more acute, the anterior portion of the thorax is more 

 distinctly punctate, the apex is less acuminated, and the lateral 

 margin of the thorax is in one continuous line with that of the 

 elytra ; when viewed laterally, the outline of the shoulders is more 

 rounded, and forms a more marked angle with the sides of the 

 thorax. 



Taken by Mr. Adams in Danes Island, on the coast of China, 

 and by him kindly presented to my collection. 



3. H. Malaccce, n. sp. 



Breviter ovatus, rotundatus, sat depressus, punctatus, fusco- 

 rufus, nitidus ; capite ad apicem leviter raarginato, intra oculos 

 undique foveolato, impunctato, rufo ; thorace lateribus sub- 

 rotundatis, basi ad medium angulato, punctato, antice rarius : 

 elytris sat latis, sensim acuminatis, punctatis ; corpore sub- 

 tus, antennis, pedibusque rufis. 



Long Corp. lin. 1 ; lat. lin, ^. 



The only species known to me which this insect resembles is 

 H. badius, from China : from this (though very closely resembling 

 it) it may be separated by several distinctive features : when 

 viewed laterally the margin of the shoulders in this species is 

 more contracted, less rounded : there is a slight, though percep- 

 tible angle formed by the margin of the thorax and elytra, which 

 does not exist in H. badius. Tlie apex of the elytra is manifestly 

 more elongate, and the punctuation also differs of the thorax. 



The species has been taken by Mr. Wallace, near Malacca. 



