Clare Island Survey, 



29. 

 AQUATIC COLEOPTERA. 



By FEANK BALFOUB BEOWNE, M.A. (Oxon.), F.E.S.E., F.Z.S. 



Read December 11, 1911. Published January 23, 1912. 



For the vice-county of West Mayo the published records of water-beetles 

 include a total of four species so that, so far as this group is concerned, the 

 Clare Island Survey has had practically virgin soil to work upon. The total 

 number of species in the accompanying lists is ninety, a number which 

 compares not unfavourably with that for other Irish counties which have been 

 worked. 



In studying this group I have only twice been able to visit the district 

 but I have been assisted by several friends, Messrs. A. W. Stelfox, B. J. Welch, 

 J. N. Halbert and the Bev. W. F. Johnson having collected water-beetles for 

 me while carrying on their own work. I am especially indebted to 

 Mr. Stelfox who not only collected on several occasions a large number of 

 specimens but also managed to find three species which, but for him, would 

 not have appeared in the lists. His discovery of Deronectes griseo-striatus on 

 Achill Island is specially noteworthy and, it may be mentioned, it was he 

 who first found the species in Ireland, bringing me a specimen from the 

 Farkmore district, Co. Antrim, in June, 1910. Mr. Halbert has also taken 

 three species which I failed to find, the most interesting of which is Octhebiv.s 

 viridis which previously has only occurred in the east and south-east of 

 Ireland. The four gentlemen mentioned, between them, collected fifty-one 

 species, a highly creditable total, considering that water-beetles were entirely 

 off their lines of work. 



In the lists of species I have not included Heloehares Hindus, Forst. 

 Without having gone very carefully into the matter, I had come to regard 

 H. lividus and H. punctatus as having been separated on insufficient grounds. 

 After mentioning this to Dr. Sharp he wrote to me that he had re-investigated 

 the matter and that they are distinct species. In West Mayo I found both 

 light and dark specimens of Heloehares but I seem to have brought home only 

 dark ones and I have since wondered whether those that were pale-coloured 



R.I.A. PROC, VOL. xxxi. A 29 



