THE AQUATIC COLEOPTERA OF THE SOLWAY DISTRICT 77 



a small part of Lanark where the Eyan Water, a tributary 

 of the Annan, has its source, a small corner of Roxburgh, and 

 also a small portion of Cumberland and of Northumberland. 



In the present paper I refer to the results of three years' 

 work — so far as my own records are concerned ; and in view 

 of the fact that the county and vice-county system of record- 

 ing distribution, as originally laid down by Watson (" Cybele 

 Britannica ") is gradually being, and will I hope soon be 

 universally, adopted by naturalists, I shall give a county 

 reference for each species. Also in referring to the distri- 

 bution in Great Britain or Ireland of any of the species, I 

 shall adopt the same system which is used by Mr. J. \\\ 

 Taylor in his " Monograph of the Land and Freshwater 

 Mollusca of the British Isles," which is now appearing, the 

 system which is officially recognised by the Conchological 

 Society of Great Britain and Ireland. 



In saying that my collecting in the district has covered 

 three years I do not wish to convey the idea that I have 

 spent three whole years at the work, but that on various 

 occasions during that time I have visited the district and 

 have spent most of the time of my visits hunting water- 

 beetles. Most of my collecting has been done in Kirk- 

 cudbrightshire, but I have done a certain amount in 

 Dumfriesshire, and much less in Wigtownshire, and on 

 the accompanying map I have marked all the stations 

 at which collections have been made. It will be seen 

 from the map that a very small part of the whole district 

 has been worked by me, so that, although my list contains 

 105 species, there are possibly others to be found in out- 

 lying parts. Although I have probably covered most of 

 the ground worked by the earlier collectors I have failed to 

 find several species recorded by them, some of which, I have 

 no doubt, would have turned up if I had searched the right 

 habitats. One gets into the habit of working certain kinds 

 of ground and of, perhaps unconsciously, neglecting others, 

 so that the results of any one collector are almost certain to 

 be imperfect in some direction. I have entirely neglected 

 the genera Sphaeridium, Cercyon, Megasternum, and Crypto- 

 pleurum, which are, some chiefly, others entirely, terrestrial, 

 so that few individuals turn up in the water-net. 



