On Aquatic Carnivorous Coleoptera or Dytiscide. 347 
punctatus ; elytris cristis duabus abbreviatis elevatis ; antennis pedibusque testaceis, 
plus minusve infuscatis. Long. 2, lat. 14 m.m. 
I see no external sexual distinctions in this species. 
This species varies greatly as to the general colour and markings; in Corsica 
very dark specimens are found, the elytra in some of them being nearly entirely 
black, this is the var. obscurior, Desb. 
Central and Southern Europe, and North Africa; Illyria, on the banks of the Isonzo; Switzerland, 
France, Spain, Corsica, Algeria and Marocco, 124. 
248. Bidessus bicristatus, n. sp.—Breviter ovalis, latus, subtus convexus, sine 
pubescentia, testaceus, prothoracis marginibus anterioribus et posterioribus, 
elytrorum sutura maculisque nigris ; elytris fortiter crebre punctatis, cristis duabus 
elevatis ; corpore subtus fortiter profundeque punctato. Long. 2, lat 13 m.m. 
Closely allied to Hydroporus bicarinatus, but broader and more coarsely punctured, 
and with the dark marks less: those on the elytra consist of a stripe along the 
suture which on the middle is dilated so as to form an angular mark, and of a 
small round mark just at the termination of the inner crista. 
Found at Jeddah in Western Arabia, by Dr. Millingen. 125. 
249. Hydroporus porcatus, Klug, M.C.—Oblongo-ovalis, subtus convexus, sine 
pubescentia, testaceus, prothoracis basi elytrorumque signaturis nigris; elytris 
erebre fortiter punctatis, crista unica elevata; corpore subtus ferrugineo, fortiter 
punctato. Long. 2%, lat. 13 m.m. 
In the male the front and middle tarsi are rather longer, and have the basal 
joint a little more dilated than in the female. 
Egypt. 126. 
250. Hydroporus dohrni, (Wehncke), n. sp.—Breviter ovalis, latus, subtus 
convexus, sine pubescentia, testaceus, elytris lineis abbreviatis fere parallelis nigris, 
corpore subtus ferrugineo, fortiter punctato; elytris fortiter, crebre punctatis, crista 
longitudinali elevata, alteraque externa obsoleta. Long. 25, lat. L$ m.m. 
South West Africa. 127. 
251. Hydroporus costipennis, Fairm. Ann, Soc. Fr. 1869, p. 187.—Breviter 
ovalis, latus, subtus convexus, sine pubescentia, subtus ferrugineus, supra testaceus, 
sat nitidus, elytris sutura signaturisque transversis nigris ; thorace parce punctato, 
striga valde obliqua ; elytris fortiter crebre punctatis, cristis duabus elevatis ; corpore 
subtus fortiter profundeque punctato. 
Ste. Marie, Madagascar. 146. 
TRANS. ROY. DUB. SOC, NS., VOL. IL. 22 
