360 On Aquatic Carnivorous Coleoptera or Dytiscide. 
This species varies in colour, form and punctuation, and also in size, and even a 
little in the thickness of the antennz. 
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, levigatus, pernitidus,. 
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. 23, lat. 1s 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. 
295. Bidessus impressus, n. sp.—Oblongo-ovalis, levigatus, pernitidus, testaceus, 
subtus nigricans, elytris fusco-testaceis; his crebre distincte punctatis, punctis. 
versus latera apicemque obsoletioribus; prothoracis lateribus fere parallelis; 
antennis (preesertim in femina) crassiusculis. Long. 3, lat. vix 13 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 antenne- 
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, levigatus, nitidus, castaneo- 
testaceus ; elytris sat crebre et fortiter punctatis, punctis lateribus et apice sub- 
tilioribus ; prothoracis lateribus subparallelis. Long. ¢ 23, ? 24, lat. 14 m.m. 
Closely allied to Bidessus impressus, but smaller, and more pallid, and with the 
antennee 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 antennee are rather shorter than they 
are in the male but not stouter. 
The specimens sent by Mr. Lawson, from Auckland, are females, and are slightly 
