Water-beetles 



(Dytiseidae & Hydrophilidae) 



of the Swedish Zoological expedition to Egypt 

 and the White Nile. 



By 



D. Sharp 



of Cambridge. 



>; 



Very little is known of the water-beetles of the "White 

 Nile. Dr. Regimbart, who has recently given us a revision of 

 the Dytiseidae and Oyrinidae of Africa (Mem. Soc. ent. Belgique 

 IV, 1895), appears to have seen few specimens from this river. 

 The little collection, made by the entomologist of the Swedish 

 Expedition Phil. Cand. I. TragArdh, that has been submitted to 

 me, is therefore of some interest, and it proves to contain several 

 new species. It is not, however, of sufficient extent to justify 

 the belief that it represents more than a small part of the White 

 Nile aquatic Coleopterous-fauna. It contains indeed no example 

 of certain genera that must certainly occur there, e. g. Cybister, 

 Copelatus, Hydrophilus — as they are found all over Africa 1 . 



1 The absence in the collection af certain genera such as e. g. Cybister, 

 Copelatus, Hydrophilus, pointed out by Sharp, is due to the manner in which 

 the animals were collected. They were, in a way, byproducts of the very 

 extensive investigations made into the fauna of aquatic plants. Sweeps with 

 the net were only made as an exception. Under such circumstances, it is quite 

 natural that species belonging to the genera mentioned above, which do not 

 live on aquatic plants, are not to be found, but that fact need not prove thai 

 the collection does not afford a rather faithful picture of the fauna of small 

 forms which it comprises. (I. Traydrdh.) 



Jayerskibld: Expedition. 10. (6) 1 



