294 1 ? ie Irish Naturalist September, 



AQUATIC COLEOPTERA. 



BY FRANK BALFOUR BROWNE, M.A., F.R.S.K-, F.Z S. 



In the present paper I am dealing with the Hydradepha^a 

 (not including the Gyrinidae) and with the Hydrophilidae or 

 Palpicornia (not including the sub-family Sphaeridiinae, 

 except the genus Cyclonotuvi). The Gyrinidae require a method 

 of collecting different from that required for the other water- 

 beetles, and the Sphaeridiinae, except the genus Cyclonotum, 

 are more commonly found out of the water than in it. 



The list of water-beetles of County Cork given by Messrs. 

 Johnson and Halbert in the " Beetles of Ireland " (Proc. 

 R.I. A., ser. iii., vol. vi., 1901) includes only 29 species of 

 Hydradephaga and 9 species of Hydrophilidae, and in giving 

 these totals I have assumed that the 14 Hydradephaga and 8 

 Hydrophilidae, described as " Common— Ulster, Leinster, 

 Munster, Connaught r '— are to be included in the list for the 

 county. 



During the five days of the Conference I found all except 

 five of the water-beetles included in the list, and discovered 

 other 19 H3'dradephaga and 16 Hydrophilidae, one of the 

 former and three of the latter being new Irish records. 



It was of course impossible in such a short visit to do 

 sufficient work to enable one to decide whether there is any 

 definite distribution east and west in the county, as has been 

 observed in the case of plants, but as a contribution to future 

 work on the subject I have followed Praeger (I.N., vol. v., p. 

 29. 1896) in his divisions into East, Mid, and West Cork. The 

 result of grouping the species according as they occurred in 

 the East, Mid, or West divisions apparently shows a some- 

 what different fauna in each division ; but it must be borne in 

 mind that water-beetles can be divided up into groups accord- 

 ing to the nature of their habitat. Without going into detail, 



