302 • Capt. F. Balfour-Browne on 



requires fiirtlier investigation, D. depressus is apparently only 

 a loch species. 



The same type of locli suits both, and they occur upon a 

 stony, gravelly, or sandy bottom, but apparently not on 

 a peaty one. Some sort of vegetation seems to be necessary, 

 but whereas in some lochs . I found the beetles on ground 

 carpeted with Lobelia dortmanni, in otiiers this weed failed 

 to produce any. The most fertile spot was usually where 

 there was a patch of Myriophyllum or other weed on a stony 

 bottom, but even such a place sometimes failed to produce a 

 single individual. 



I examined seventeen lochs without finding either species^ 

 and the following is a list of these : — 



" Upper Loch," Lochmaben. Dumfries. 



Clearburn L. Selkirk. 



L. Smaddie. Ku'kcudbright. 



L. Lurkie. ,, 



L. Arthur or Lotus L. Kirkcudbright. 



Knocksting L. „ 



Lochenbreck L. „ 



Little Dornell L. „ 



Elates Mill L. (by Woodhall L.). Kirkcudbright. 



Dry Loch (Dungeon of Buchan), „ 



L. Dow (Craignaw). „ 



Craiglee L. (top of Craiglee). „ 



Long L. of Glenhead. „ 



L. Minnoch. „ 



L. Enoch. „ 



L, Arron. „ 



Lu Neldricken. „ 



In the case of one or two of these tlie peaty bottom perhaps 

 made the habitat unsuitable {e. g., Little Dornell L., Blates 

 Mill L., and "Upper" L.), while in others perhaps altitude 

 excluded them [e. g., L. Enoch, 1600 ft. ; L. Arron, 1400 ft. ; 

 Ciaiglee L., 1700 ft. ; and L. Dow, 1300 ft.), but in the case 

 of most of the others I cannot imagine why I found neither 

 species, except tliat I was unlucky. Why, for instance, 

 should L. Neldricken not have either of them, when both 

 L. Valley and L. Narroch possess elegcms? The Long L. of 

 Glenhead is to all appearance quite as suitable for the species 

 as the E-ound L., which contains elegans. Knocksting L. and 

 L. Arthur I worked thoroughly and over very promising 

 ground, and yet without result. L. Minnoch, lying between 

 Lochs Harrow and Dungeon, I worked three times, and 

 examined it all round, and yet failed to find any water-beetle 

 at all. Such a resnlt is very rare in my experience .Lochen- 



