720 On Aquatic Carnivorous Coleoptera or Dytiscide. 
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 angustatus, niger, antennis pedibusque anterioribus et intermediis 
rufis, his femoribus late nigricantibus, pedibus posterioribus piceis; epipleuris 
elytrorum ultra medium latis et planatis. Long. 203, lat. 12 m.m. 
In the male of this species the anterior tarsi are rather 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, Monrovia). 1060. 
1131. Cybister 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 ultra medium latis 
et planatis. Long. 24, lat. 183 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, (Cameroons, 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. 173 m.m. 
This species differs 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 large 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. 
