On Aquatic Carnivorous Colcoptera or Dytiscida. 347 



punctatus ; elytris cristis duabus abbreviatis elevatis ; antennis pedibusque testaceis, 

 plus minusve infuscatis. Long. 2, lat. li 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 ; lUyria, on the banks of the Isonzo ; Switzerland, 

 France, Spain, Corsica, Algeria and Marocco. 124. 



24S. 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 If 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 

 ci-ebre fortiter punctatis, crista unica elevata ; corpore subtus ferrugineo, fortiter 

 punctato. Long. 2i, 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. 2j-, lat. If m.m. 



South West Africa. 127. 



251. Hydroporus costiponnis, Fairm. Ann, Soc. Fr. 18G.9, p. 1S7. — Breviter 

 ovalis, latus, subtus convexus, sine pubescentia, subtus ferrugineus, supra testaceu^^, 

 sat nitidus, elytris sutura signaturisque transversis nigris; thorace parce puiictato, 

 striga valde obliqua ; elytris fortiter crebre punctatis, cristis duabus elevatis ; corpoir 

 subtus fortiter profundeque punctato. 



Ste. Marie, Madagascar. 146. 



TBANS. ROY. DUU. SOC , N S., VOL. II - 2 Z 



