Un Aquatio Carnivorous Colcoptera or DytiscidcB. 543 



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 I64 m.m. broad. 



Motschoulsky's description of Cy bister 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 doiug. 



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 intermediis testaceis, his tarsis piceis ; pedibus 

 posterioribus nigricantibus, femoribus ad apicem late rufis ; elytris versus apicem 

 subtilius coriaceo-rusfulosis. Long'. 30i, lat. IGi m.m. 



The male has the front tarsi large attaining Z\ 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 epipleurse 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 beheve will prove to be characteristic. 



A female of this species existed in Dej can's collection, where it was ticketed as a 

 variety of " Dytiscus limbatus." 



India, (Sylhet;. 1094. 



1164. Cybister javanus, Aube, Spec. p. 59. — Major, ovalis, latus, supra olivaceo- 

 niger, capite anterius prothoraceque ad latera testaceis, elytris vitta intramarginali, 

 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. 19i m.m. 



