702 On Aquatic Carnivorous Coleoptera or DytiscidoB. 



anterioribus rufis : prothorace raargine laterali elevato ; prosterno a margine 

 anteriore ad apicem profunde sulcato. Long. 16, lat. 8f m.m. 



In the male the front tarsi are not large ; their claws are peculiar, very unequal 

 ill length, each has a swelling at the extreme base, and is abruptly bent just 

 beyond this, the front one is elongate and slender, while the hind one is much 

 shorter and is sinuate ; the undersurface is occupied with rather large, nearly cir- 

 cular, palettes, the basal fringing hairs are elongate and well developed, and there 

 is no pubescent area between them and the palettes. The intermediate tarsi are 

 slender, and without sexual pubescence, but their claws are very unequal in length, 

 the outer one being elongate. The female has no sexual sculpture. 



This interesting little species can be readily distinguished from all its allies by 

 the fact that the thorax is flattened or depressed close to the side so as to give the 

 lateral margin the appearance of being elevated. It varies somewhat in the colour 

 of the upper surface, which is in some cases more tinctured with green and with a 

 metallic lustre than it is in others. 



Australia, ( S wan River) . 1118. 



1098. Spencerhydrus latecinctus, n. sp. — Parvus, oblongo-ovalis, sat convexus, 

 supra piceo-niger, capite anterius prothoraceque ad latera testaceis, elytris latissime 

 testaceo-cinctis ; subtus piceo-rufus, pedibus quatuor anterioribus rufis ; prosterno 

 a margine anteriore ad apicem sulcato. Long. 181, lat. 10 m.m. 



In the male the front tarsi are moderately large, their claws are greatly and 

 abruptly curved, and the anterior one is nearly twice as long as the other ; the 

 undersurface is furnished with rather large elliptico-circular palettes, and the basal 

 fringing hairs are well developed, there being no pubescent area between these 

 and the palettes. The intermediate tarsi are simple, their claws rather elongate 

 and slightly unequal. The female is unknown to me. 



This and the following species are readily distinguished from the allies by the 

 very broad lateral yellow band of the wing-cases, even at the apex it is very 

 broad. 



Australia. 1119. 



1099. Spencerhydrus semiflavus, n. .sp. — Parvus, oblongo-ovalis, sat convexus, 

 supra viridi-olivaceus, oinnium latissime testaceo-cinctus ; subtus testaceus ; pro- 

 sterno a margine anteriore ad apicem sulcato. Long. 19, lat. 10 m.m. 



I have seen only the female of this species ; it has on the thorax near the sides 

 numerous short, rather fine scratches, 



Although probably closely allied to S. latecinctus, I think this will prove a dis- 



