136 [ June ' 



This species can only be confounded with the most dull varieties 

 of marinus and opacus, but it is more dull than any of them, and 

 when examined with a power of about 60 magn. it is seen that the 

 dullness arises from the surface being very finely alutaceous. The 

 species is also in remarkable contrast to the two for which it has been 

 mistaken, by having the claws of the middle and hind tarsi pale 

 yellow, although the apex of the tarsus is piceous. I do not know the 

 female. The male has the front tarsi broadly dilated, and the eedeagus 

 (figs. 12) is different from that of any other, being perhaps most like 

 that of G. colymbus. This species is an addition to the British Cata- 

 logue ; it is not the opacus of our collections. Suffrian 70 years ago 

 misinterpreted Sahlberg's description, and he has been followed by 

 others until his error was detected by Seidlitz in 1887, and by E.egim- 

 bart in 1891. The G. opacus of our British collections is the species 

 which I shall here characterise as edwardsi ; the dull variety of opacus 

 from Invercannich, mentioned by me in 1868 as " very curious " is, 

 however, the real opacus. 



As the descriptions and remarks of Seidlitz and Regimbart con- 

 tain no reference to the two most important characters of opacus, (viz., 

 the structure of the. sedeagus and the colour of the claws), I addressed 

 myself to my old friend, Dr. J. Sahlberg, of Helsingfors, and he has 

 been so good as to send me two of the original types from his grand- 

 father's collection, and a small series of more recently collected 

 examples from various parts of Scandinavia, and showing that our 

 Scottish mountain Gyrinus is really the same species as the Scandinavian 

 one. I am also indebted to Dr. Sahlberg for informing me that Count 

 Mannerheim pointed out Suffrian's error in 1847 (Stettin, ent. Zeit., p. 

 209), a fact with which I was previously unacquainted. This was 67 

 years ago, and yet in the latest European Catalogue, " opacus, Sahib.," 

 is placed as a variety of marinus, G-yll., no doubt as a result of the 

 belief that " opacus, Suffr.," is the same species as that of Sahlberg. 



The species has hitherto only been found in Scandinavia and 

 Iceland ; to which we may now add Scotland. I found it at Invercan- 

 nich in July, 1866, at Braemar in June, 1871, and again in June, 1909. 

 It is no doubt a boreal form, and comparatively solitary in habits. My 

 specimens were found, I believe, at a considerable elevation in company 

 with G. minutus. After G. minutus it is the most distinct and isolated 

 of our British Gyrini. G. opacus thus occurs from arctic Norway and 

 Lapland southwards to the Highlands of Scotland, and its occurrence 

 in the latter country is a matter of considerable interest. Dr. Sahlberg 



