THE AQUATIC COLEOPTERA OF THE NORTH EBUDES 155 



one or more specimens appeared under most of them. The 

 specimens were easily captured in the fingers, and as they 

 were common I noted the proportion of the sexes, and in 

 twenty minutes I had counted 2 I females and I 2 males. 



In the loch Gammarus was common, but I only saw one 

 or two newts, and it certainly did not look a suitable place 

 for them. A large proportion of the D. lapponicus were 

 soft and recently emerged specimens. 



The list of species is as follows : 



Deronectes griseo - striatus Dytiscus lapponicus (common). 



(common). Gyrinus natator. 



Hydroporus obscurus (i). Anacasna globulus (2). 



Agabus arcticus (common). Limnebius truncatellus (i or 2). 

 A. sturmii (2). 



The H. obscurus, A. globulns, and L. truncatellus occurred 

 at a spot where a trickle of water fell over the western bank 

 into the loch from a patch of boggy ground. 



My experience with regard to Dytiscus lapponicus there- 

 fore differs in one respect from that of other British 

 collectors, since I found in two cases the females were 

 more common than the males. The habitat of the species 

 also varied to some extent, and the Lochan-na-Beinn Buidhe 

 was, from my previous experience, a most unlikely place to 

 find the species. One or two other lochans on the western 

 side of the island, in which D. griseo-striatus and A. arcticus 

 were common, would possibly have yielded D. lapponicus 

 if I had carefully turned over the stones. 



For this kind of collecting, calm weather is essential, as 

 a ripple on the water makes it impossible to see the Beetles 

 when a stone is turned over, but, although King stated that 

 sunshine was essential, I took the species on Ben Buidhe 

 while the mist was down on the higher ground just above 

 the loch. In the last-named place I found one full-grown 

 larva of the species, and that was the only specimen I saw. 



The proportion in the numbers of the sexes is a point 

 of some considerable interest. Of those who refer to the 

 dominance of the male, Buchanan White mentions, in 

 referring to his visit to Mull in the beginning of September, 

 that numbers of full-grown larvae were about. Somerville 



