Deronectes depressus, Fab., and elegans, Panzer. 295 
about 400 feet above sea-level, and within 2 miles of the 
main road between Carlisle and Newcastle, so that it was not 
difficult to get at. The day of my visit was not propitious ; 
it began to rain heavily just as I got to the tarn, and I spent 
a miserable fifteen minutes paddling about at the edge, 
during which time I collected five species of Hydradephaga, 
and among the few specimens were two of Bold’s “ large and 
dark elegans.” 
On an examination of these a few days later, and on com- 
parison with some freshly caught specimens from the Nith 
at Dumfries, I began to suspect that the ‘Talkin Tarn indi- 
viduals were the ‘‘depressus”’ referred to by Ste. Clair 
Deville, and I returned to the tarn and collected a number of 
specimens for further examination. 
During August I examined a number of lochs and streams 
in the south of Scotland (Selkirk, Dumfries, Kirkcudbright, 
and Ayr), and definitely came to the conclusion that there 
were two species ; but I was also greatly struck by the extra- 
ordinary distribution of the rarer one, which occurred in only 
a few lochs scattered about the district. Shortly after that, 
military duties, illness, and a long convalescence intervened, 
and it is only recently that I have again taken up the matter, 
and during August of last year 1 explored a number of 
the Galloway lochs with a view to further investigating 
the distribution there of the form which I take to be the 
depressus of Fabricius. 
The characters upon which the two species can be separated 
are three in number: (1) the shape of the thorax in ¢ and 
?, (2) the form of the anterior tarsal claws of the ¢, and 
(3) the form of the eedeagus. 
In general appearance the two species are usually very 
much alike, the colour-plan being similar, but, as a rule, the 
northern species is rather larger than the other. ‘The range 
of colour-tone in the common species is greater than in the 
northern one, which is always dark, the yellow being reduced 
to aminimum, the black always occupying a large extent of 
the surface of the elytra. In the common species, especially 
in specimens from the south, the yellow is usually lighter in 
{one and the black more limited, but the relationship between 
the black and yellow seems to be related to habitat and to 
climatic conditions, as is the case with Platambus maculatus, 
Deronectes griseo-striatus, and some other Hydradephaga. 
In the Scottish lochs I can find no difference whatever 
in colour-tone between the two species. 
20* 
