912 On Aquatic Carnivorous Coleoptera or DytiscidcB. 



almost without spinules on the lower or anterior face ; their femora bear numerous 

 quite short setae. The last two abdominal stigmata are small. The females have 

 on the front and middle tarsi quite short spines at the edges beneath. The front 

 tarsi of the male are rather large, they have well developed basal fringing hairs 

 and the basal palettes on the undersurface are considerably larger than the others ; 

 the middle tarsi are scarcely incrassate, but bear small palettes beneath. The 

 female is destitute of sexual sculpture. 



This isolated insect is least widely separated froni Sandracottus, but it differs 

 greatly therefrom in appearance; and the short spines on the middle femora, the 

 smaller terminal abdominal stigmata, the more highly developed male tarsi, and 

 the greater approximation of the hind coxa to the middle ones, call for its separa- 

 tion. 



This species has a wide geographical range in the warm zone of the eastern 

 hemisphere. 



I. 74.— Genus GRAPHODERES. {Vide p. 692.) 



Eleven species, whose individuals are of rather large size (half an inch or rather 

 more of length), form this aggregate, they have a polished surface, are of a yellow 

 colour, with the wing-cases uniformly speckled or vermiculated with black. The 

 antennal portion of the head is moderately large, and the eyes are of moderate size, 

 the portion of the head between them being considerably more than twice the 

 transverse width of the eye as seen from the front. The prosternal process is 

 short, broad and rounded. The hind coxse are very large, and their front border 

 approaches near or very near to the middle coxae ; the wing of the metasternum 

 forms an extended slender band, becoming broader near its termination. The 

 coxal lines are fine and short, but distinct in their huider portions, they are a good 

 deal turned outwards on the coxal lobes, and mark ofi' a moderately broad supra- 

 articular border : the coxal notch is absent or extremely rudimentary. The hind 

 legs are rather highly developed for swimming. The two terminal stigmata are 

 moderately large. The middle legs are moderately slender, their tibiae bear distinct 

 spinules on their anterior or lower face, their femora have short, or rather short 

 setae ; the females have on the front and middle tarsi, short, rigid sj^inules. The 

 front tarsi of the males are rather large, and highly developed, with beautiful basal 

 fringing hairs, and with the basal palettes a good deal larger than the others. The 

 middle tarsi are in all the species except one (Hydaticus austriacus) provided with 

 palettes beneath and have the basal joints more or less thickened. The females 

 vary as to their sexual sculpture, sometimes they have none, while in other species 

 there is an extremely highly developed tuberculation, rendering the wing-cases 

 very uneven and rough. 



The genus is confined to the northern portion of the Old and New Worlds. 



