912 On Aquatic Carnivorous Coleoptera or Dytiscide. 
almost without spinules on the lower or anterior face ; their femora bear numerous 
quite short sete. 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 from 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 coxe are very large, and their front border 
approaches near or very near to the middle coxee; 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 hinder portions, they are a good 
deal turned outwards on the coxal lobes, and mark off 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 tibie bear distinct 
spinules on their anterior or lower face, their femora have short, or rather short 
setze ; the females have on the front and middle tarsi, short, rigid spinules. 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 jomts 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. 
