7:20 On Aquatic Carnivorous Coleoptera or Dijtiscidce. 



I expect from Boheman's description of Cybister marginicollis (Ins. Caff. I. p. 

 235) that it is an insect allied to this species, possibly actually this species, although 

 some of the details he mentions seem scarcely applicable. 



West Africa, (Gaboon, Isubu, Portuguese Guinea). 1059. 



1130. Cybister irritans, Dohrn, Stet. Ent. Zeit. XXXVI, p. 290.— Ovalis, sat 

 latus, anterius augustatus, niger, antennis pedibusque anterioribus et intermediis 

 rufis, his femoribus late nigricantibus, pedibus posterioribus piceis ; epipleuris 

 elytrorum ultra medium latis et planatis. Long. 20i, lat. 12 m.m. 



In the male of this species the anterior tarsi are leather small, and the pubescent 

 area of the basal joint is but slightly developed ; the basal joint of the intermediate 

 tarsus bears beneath a patch of long hairs, the patch being in form an elongate 

 narrow triangle, and the second joint has also a large development of similar hairs ; 

 the female has no sexual sculpture. 



Western tropical Africa, (Guinea, ^lonrovia). 1060. 



1131. Cj'^bister deplanatus, n. sp. — Ovalis, latus, anterius angustatus, supra 

 parum convexus, olivaceo-niger, pedibus anterioribus et intermediis nigris, rufo- 

 variis, posterioribus piceis, antennis rufis ; epipleuris elytrorum ulti'a medium latis 

 et planatis. Long. 24, lat. 131 m.m. 



This species differs from C. irritans, by its larger size and broader form, and 

 by the rather greater development of the male anterior tarsi, the dilated joints of 

 which have a greater development in the transverse direction. 



Western tropical Africa, (Oameroons, Cape Coast Castle). 1061. 



1132. Cybister operosus (Dej.) n. sp. — Ovalis; latus, sat convexus, supra olivaceo- 

 niger, nitidus, pedibus anterioribus et intermediis nigris, rufo-variis, posteriori- 

 bus nigris, antennis rufis ; epipleuris elytrorum ultra medium latis et planatis. 

 Long. 31, lat. ITo m.m. 



This species difters from C. deplanatus, by its larger size, and the greater develop- 

 ment of the male front tarsi ; these are moderately large, and have a distinct though 

 not larare basal area of pubescence beneath : the middle tarsi have a rather large, 

 moderately broad patch of long sexual hairs on the basal joint, and a smaller patch 

 on the following joint. The female has no sexual sculpture. 



The fine scattered punctures which are seen on the upper surface of the two pre- 

 ceding species are scarcely to be detected in the present one. 



Madagascar. 1062. 



