On Aquatic Carnivorous Coleoptera or Dytiscidcs. 733 



The male anterior tarsi are small ; and on the intermediate feet the three basal 

 joints are furnished beneath with rather short sexual pubescence, the patch on the 

 basal joint is broad, that on the third joint quite narrow, the one on the second 

 joint being intermediate in width. The female has no trace of any sexual sculp- 

 ture. 



The species is readily distinguished amongst its allies by its small size : it varies 

 somewhat in form ; some individuals being notably more elongate than others, it 

 also varies somewhat in the colour of the undersurface, this being sometimes nearly 

 black, more rarely piceous red. 



Algeria, Senegal, Madagascar. 1076. 



1146. Cybister occidentalis, Aube, Trogus occidentalis, 21. C. — Latus, ovalis, 

 parum convesus, nitidus, niger, parum olivaceus, capite anterius prothoraceque ad 

 latera testaceis, elytris margine externo (cum epipleuris) late testaceo ; pedibus 

 anterioribus rufis, femoribus fusco-maculatis, intermediis piceis, femoribus basi 

 apiceque rufescentibus, posterioribus nigricantibus, femoribus angulo externo 

 posteriore recto : antennis rufis ; elytrorum epipleuris versus apicem sat latis et 

 planatis. Long. 33, lat. 19 m.m. 



The male has the front tarsi rather large in the transverse direction ; the 

 intermediate feet bear patches of moderately short sexual pubescence, on the 

 three basal joints, the basal patch is broader than the others, that on the thirdjoint 

 being quite narrow, the claws are rather long and stout, curved and distinctly 

 unequal ; in the hollow just in front of the articulation of the swimming legs there 

 are four or five coarse, short, raised ridges. The female has a well marked sexual 

 sculpture on the wing-cases and thorax ; on the former there are fine scratches of 

 variable length, some of them elongate, they are directed in the long axis of the 

 body and show a tendency to converge or anastomose here and there, at the base 

 they extend from the scutellum to the shoulder, elsewhere they reach neither to 

 the suture nor to the lateral margin although they invade the inner portion of the 

 yellow band ; they reach about four-fifths of the way to the apex ; on the thorax the 

 scratches are short, and not numerous, they are also absent altogether from the disc ; 

 on the head there are some fine scratches behind the eye. 



In this as in the following species, the yellow band at the apex of the elytra 

 does not terminate in quite a point at the suture, so that it is distinctly connected 

 with that on the other wing-case. 



I have seen specimens of this species in more than one collection, said to be from 

 Montevideo and Buenos Ayres, but I believe erroneously. 



Owba. 1077. 



S B 3 



