360 On Aquatic Carnivorous Coleoptera or Dytiscidai. 



This species varies in colour, form and punctuation, and also in size, and even a 

 little in the thickness of the antennae. 



The male has the front and middle tarsi rather broader than in the female. 



Australia, Tasmania ; apparently common, (Melbourne, Port Denison). 80. 



294. Bidessus inornatus, n. sp. — Oblongo-ovalis, angustulus, Isevigatus, pernitldus, 

 rufo-testaceus, elytris obscurioribus, subtus lateribus infuscatis ; elytris apice et 

 versus suturam crebre subtiliter punctatis ; thorace basi quam medio fere angus- 

 tiore; antennis tenuibus Long. 2|. lat. 1| m.m. 



Closely allied to H. amabilis, readily distinguished by its more parallel and 

 narrower form, and the more parallel-sided thorax. 



I have seen only one individual, which is a male, and has the front and middle 

 tarsi (especially these latter) very much broader than they are in H. amabilis. 



West Australia, (Duboulay). 81. 



29.5. Bidessus impressus, n. sp. — Oblongo-ovalis, laBvigatus, pernitidus, testaceus, 

 subtus nigricans, elytris fusco-testaceis ; his crebre distincte punctatis, punctis 

 versus latera apicemque obsoletioi'ibus ; prothoracis lateribus fere parallehs ; 

 antennis (preesertim in femina) crassiusculis. Long. 3, lat. vix li m.m. 



Closely allied to Hydroporus amabilis, but with the thorax narrower behind, 

 the punctures of the elytra more distinct, and the prosternal process narrower and 

 less parallel. 



The male has the front and middle tarsi moderately dilated, and the antennae 

 longer and more slender than in the female. 



The specimens in my collection labelled Australia bear no special locality and 

 may perhaps be actually from New Zealand. 



New Zealand, and Australia. 82. 



296. Bidessus plicatus, n. sp. — Oblongo-ovalis, laevigatus, nitidus, castaneo- 

 testaceus ; elytris sat crebre et fortiter punctatis, punctis lateribus et apice sub- 

 tilioribus ; prothoracis lateribus subparallelis. Long. $ 2i, p 21, lat. li m.m. 



Closely allied to Bidessus impressus, but smaller, and more pallid, and with the 

 antennae of the female considerably more slender. 



The male has the front and middle tarsi a good deal more dilated, and the elytra 

 are more elongate ; the breast and abdomen are black. In the female the elytra 

 are short, and not so parallel-sided, the colour of the breast and ventral segments 

 is more or less infuscate testaceous, and the antennae are rather shorter than they 

 are in the male but not stouter. 



The specimens gent by Mr. Lawson, from Auckland, are females, and are slightly 



