On Aquatic Carnivorous Coleoptera or Dytiscide. 659 
turisque disjunctis, testaceis ; pedibus posterioribus robustis, tarsorum marginibus 
posterioribus sat longe ciliatis. Long. 143, lat. 82 m.m. 
This species is very similar to H. jucundus, but the yellow marks on the elytra 
are isolated from one another and less extensive, and the thorax is a little different, 
it being rather shorter and more curved at the sides near the posterior angles which 
are more rounded, it is more punctured near the sides and less evenly convex 
transversely ; so that in the form of the thorax the species makes a distinct approach 
to the peculiar Prodaticus pictus (No. 1005). The sexual characters both of the 
male and female seem to he quite the same as in H. jucundus, except that the 
female has no distinct impressions on the lateral part of the thorax, the surface 
there being, however, uneven and obscurely corrugated. 
Sinai, Egypt, Nubia. 1021. 
1026. Hydaticus jucundus, Reiche, M.C.—Ovalis, sat latus, nitidus, rufo-testaceus, 
vertice prothoraceque basi in medio elytrisque nigris, his margine externo signa- 
turisque irregularibus plus minusve transversim dispesitis testaceis; pedibus 
posterioribus robustis, tarsorum marginibus posterioribus sat longe ciliatis. Long. 
144, lat. 9 m.m. 
The male front tarsi are highly developed, the fringing hairs being very long, and 
the palettes large, the basal ones being particularly large; the middle tarsi are 
somewhat broadly dilated : the female has some coarse irregular impressions on the 
lateral parts of the thorax ; in this sex there are some fine scattered punctures on 
the wing-cases, which are almost entirely absent in the male. The male has an im- 
pression at the apex of the last ventral segment, causing the hind margin to be 
depressed in the middle and to appear emarginate: the female has a longitudinal 
impression which reaches just as far as, but does not depass, the hind margin. 
This species seems to be somewhat variable in size and in the yellow marks of 
the elytra; these marks especially near the sides and extremity are dotted with 
black. 
Abyssinia. 1020. 
1027. Hydaticus dregei, Aubé, M.C.—Ovalis, parum latus et convexus, leevigatus, 
nitidissimus, rufo-testaceus, vertice, prothorace basi in medio elytrisque nigris, his 
signaturis irregularibus margineque externo testaceis; pedibus posterioribus sat 
gracilibus, tarsorum marginibus posterioribus haud longe ciliatis. Long. 1332, 
lat. 77 m.m. 
On the front tarsi of the male the fringing hairs are very highly developed and 
the palettes are of very unequal sizes, the basal ones, especially the posterior one, 
being of large size; the middle tarsi are only moderately dilated: the female has 
4Q 
TRANS. ROY. DUB. SOC. N.S., VOL. II. 
