740 On Aquatic Carnworous Coleoptera or Dytiscide. 
The front and middle tarsi of this species are similar to those of C. confusus ; but 
the cedeagus presents constant and well marked differences; its inferior lobe 
becomes narrower till close to the termination, when it becomes much broader, its 
extremity is broadly emarginate, so that it has a furcate appearance, and is also 
arched in the transverse direction; the dorsal lobe terminates in two processes 
which do not extend to the apex, and which diverge from one another before their 
termination, the apices however are again a little incurved, but not contiguous, 
bemg separated in the condition of repose by a broad longitudinal elevation which 
runs along the middle of the under lobe. The female has a highly developed 
sexual sculpture, similar to what exists in C. confusus, but less distinct on the disc 
of the thorax, and absent from a rather wider space along the suture of the wing- 
cases. ‘lhe epipleurz of the elytra are flattened and obliquely horizontal, and rather 
broad, the torsion commences very close to the shoulder, and ceases in a gradual 
manner about the hind margin of the second ventral segment. 
The species is a rather variable one; and there may be distinguished three 
varieties : the first is of short, convex form a good deal narrowed in front, and the 
sculpture of the female on the thorax and elytra is comparatively less developed, 
extending on the latter only three-fifths of the length towards the extremity ; this 
is especially common in northern China and Mantchuria if I may judge correctly 
from the material before me ; the second form is more elongate, and rather flatter 
and the sculpture of the temale is nearly as largely developed as in C. confusus, 
extending four-fifths or five-sixths of their length ; I have individuals of this variety 
from Shanghai. ‘The third form is broad and robust, and the yellow band of the 
elytra has a tendency to be prolonged nearer to the suture at the extremity, and 
the female sculpture is largely developed ; this variety occurs I believe in Southern 
Hindostan (Madras). In all the variations of this abundant insect the form of the 
cedeagus remains absolutely without variation; the varieties in colour, form, &c., 
already alluded to, merge quite gradually into one another by intermediate specimens. 
Mantchuria, China, Formosa, Southern India. 1088. 
1158. Cybister guerini, Zrogus guerim, M.C_—Ovalis, niger, capite anterius 
prothoraceque ad latera testaceis, elytris vitta intramarginali testacea, ad apicem 
haud argute hamato-dilatata, suturam haud attingente, pedibus anterioribus et 
intermediis rufis, femoribus late nigricantibus, tibiis tarsisque intermediis tere nigris. 
Long. 34, lat. 193 m.m. 
The male has the front and middle tarsi the same as in C. confusus and D. 
limbatus ; and in the structure of its ceedeagus is intermediate between the two ; the 
female has a highly developed sexual sculpture, the thorax being entirely covered with 
irregular scratches, and the elytra bearing elongate longitudinal scratches, these 
