On Aquatic Carnivorous Coleoptera or Dytiscide. 743 
This species is closely allied to C. ventralis, but is smaller, and the elytra are 
finely coriaceous-rugulose in their hinder part. 
A female, possibly belonging to this species, agrees closely with the corresponding 
sex of C. crassus, except that it is more elongate and less convex; if it be really the 
female of this species it is of more elongate form than the male: it is 30% m.m. 
long, by 164 m.m. broad. 
Motschoulsky’s description of Cybister chinensis is very deficient, but as 
the present is the only species known to me to which it is applicable, I have 
adopted the name with some doubt as to the propriety of so doing. 
China, (Mus. Castlenau). 1093. 
1163. Cybister crassus, n. sp.—Ovalis, robustus, convexus, supra nigricans, 
capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali, versus 
apicem hamato-dilatata, testacea; corpore subtus variegato, ex parte majore tes- 
taceo, prosterno pectoreque in medio nigricantibus, abdomine testaceo nigroque 
fasciato; pedibus anterioribus et intermedius testaceis, his tarsis piceis ; pedibus 
posterioribus-nigricantibus, femoribus ad apicem late rufis; elytris versus apicem 
subtilius coriaceo-rugulosis. Long. 303, lat. 162 m.m. 
The male has the front tarsi large attaining 3z m.m. in the transverse direction ; 
the intermediate feet as in the allied species. ‘The female has a highly developed 
sexual sculpture, the thorax being covered with curved irregular scratches, and 
the elytra with deep elongate ones, which extend about four-fifths of the length, 
and either reach quite to the suture or leave a narrow elongate space along it 
smooth ; the epipleuree in this sex are flattened and obliquely perpendicular, the 
torsion commencing near the base, and disappearing in a gradual manner about 
the hind margin of the second ventral segment. 
This species is larger than the preceding one to which it is very closely allied ; 
although it and the three preceding species are so extremely similar, the oedeagus 
presents in each slight distinctions, which I believe will prove to be characteristic. 
A female of this species existed in Dejean’s collection, where it was ticketed as a 
variety of ‘ Dytiscus limbatus.” 
India, (Sylhet). 1094. 
1164. Cybister javanus, Aubé, Spec. p. 59.—Major, ovalis, latus, supra olivaceo- 
niger, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginall, 
versus apicem hamato-dilatata, testacea ; corpore subtus variegato, prosterno pectore- 
que in medio nigricantibus, abdomine ex parte majore fuscescente, segmentis ad latera 
testaceis ; pedibus anterioribus et intermediis testaceis, his tarsis piceis ; pedibus 
posterioribus nigricantibus, femoribus ad apicem rufis; elytris versus apicem subtiliter 
coriaceo-rugulosis. Long. 34, lat. 193 m.m. 
