Water Beetles of Japan. 47 
obscure yellow points not distinctly connected with the 
stripe. The three usual lines of punctures are very dis- 
tinct, the external row less so than the two others ; the two 
or three basal points of the external row are placed in the 
yellow lateral stripe, the three or four following ones just 
at its edge. The underside of the head is pitchy red, with 
the parts of the mouth yellowish. The prosternum is red- 
dish-yellow ; the front legs are entirely yellow ; the middle 
of the breast is reddish ; the intermediate portion yellow ; 
the extreme outer margin (very narrowly) black. The 
middle legs are yellow, with the tibige slightly darker than 
the femora ; their tarsi pitchy black ; their outer claw 
larger than the inner one. The abdomen is reddish ; the 
hind margins of the segments narrowly pitchy ; the ex- 
treme sides also a little pitchy, and the basal segments with 
a pale spot at the sides. The hind femora are reddish ; 
the tibiae and tarsi pitchy black ; the spurs of the former 
reddish. 
The much more convex form, and the different colour 
of the insect beneath, will prevent this species being con- 
founded with any of the forms of C. tripiinctatus. It is 
also very different in form from C. scutellaris, from which 
morever the unequal claws of the intermediate tarsi readily 
separate it (as far as the male sex is concerned, at any 
rate). A single specimen only has been found, at Mino, 
near Osaka. 
3. Gybister tripunctatus, 01. Abundant in Nipon and 
Kushiu. These Japanese specimens cannot be considered 
specifically identical with our European C. africanus, 
which is now considered a form of tripunctatus ; they 
may indeed ultimately prove to be a distinct species from 
any yet described ; but it would be premature to consider 
them so at present, so much yet remaining to be done for 
the accurate discrimination of these difficult and variable 
species. 
4. Cybister brevis, Aube. Abundant in Nipon and 
Kushiu. This species was described by Aube from a 
single female individual. He supposed the male would 
not possess the remarkable punctuation on the head and 
thorax which he descnbed in the female ; but in this he 
was wrong, the sexes are similar in every external point 
except the structure of the tarsi. 
5. Hydaticus Adamsi, Clark. Rather rare ; under 
