On Aquatic Carnivorous Coleoptera or Dytiscicfce. 363 



gracilibus, tibiis anterioribus sat latis ; tarsis anterioribus et intermediis fortiter 

 dilatatis tarsis posterioribus gracilibus. Long. 3, lat. vix I2 m.m. 



P Oblongo-ovalis, sericeo-subopaca, rufescens, elytris pectoreque obscurioribus ; 

 elytris basi sparsim apice crebre punctatis ; antennis brevioribus, crassiusculis, tibiis 

 anterioribus latis, tarsis posterioribus crassiusculis. Long. 2$ m.m. 



The sexes of this species have the appearance of being quite distinct species. 



Australia, (King George's Sound, Swan River.) 89. 



304. Bidessus dispar, n. sp. — Oblongo-ovalis, brevis, obscure castaneus, elytris 

 crebre punctatis, tibiis anterioribus et tarsis posterioribus sat gracilibus. Long. 2i, 

 lat. 1 m.m. 



Mas, nitidulus, elytris sat fortiter punctatis, antennis gracilibus, tarsis anterioribus 

 et intermediis leviter dilatatis. 



Fern., (a.) subopaca elytris subtiliter punctatis, antennis crassis. 

 (b.) opaca elytris obsolete punctatis, antennis crassis. 



In this species there exists two forms of the female and the sexual characters 

 are very remarkable ; besides those mentioned above, the hind legs of the male are 

 a little lonsrer and more slender than those of the female. 



Australia, (Swan River). 90. 



305. Bidessus occultus, n. sp. — Sub-oblongus, parum elongatus, castaneo- 

 testaceus, capite obscuriore ; elytris crebre subtiliter punctatis ; coxis posterioribus 

 paxce subtiliter punctatis. Long. 1|, lat. 1 m.m. 



This little species differs from Hydroporus lacustris (No. 319), by its smaller size 

 more strongly punctured el}i;ra and paler under surface. It is still closer to some of 

 the smallest varieties of Hydroporus affinis (^No. 318), but it is still smaller, and is 

 of different form, its upper surface being flatter, and the outline much less acuminate 

 behind and the wing-cases are without paler markings. I have seen only a single 

 individual. 



Arabia, (El Hedjaz. Dr. C. jSIillingen). 1128. 



306. Bidessus perforatus, n. sp.^-Clypeo antice incrassato, sed vix marginato ; 

 oblongo-ovalis, brevis, rufo-testaceus, elytris sordide testaceis obsoleteque parce 

 fusco-adspersis, fortiter sat crebre punctatis, fere nudis : coxis posterioribus abdom- 

 inisque segmentis basalibus utrinque fortiter punctatis. Long, vix 2, lat. 1 m.m. 



The only two specimens I have seen of this distinct little species, have the front 

 and middle tarsi very slender, and are probably females. The prosternal process is 

 strongly margined at the sides. 



China, (Kiu Kiang, Mr. Geo. Lewis). 106. 



TRASS. BOY. DITB. SOC. S.S., VOL. n. 



