Deronectes depressus, ab., and elegans, Panzer. 301 
and “ (B) H. depressus, Gyll.”” The sex of the individuals 
drawn is not mentioned, but by the shape of the thorax A is 
more like depressus, while the dark colouring of B agrees 
with his description of that species, the shape of the thorax in 
his drawing suggesting either a @ depressus or a 3 elegans. 
Murray gives //. elegans, Illiger, as our British species, 
with the synonyms “ depressus, Aubé, Steph., not Fab., 
brevis, Sturm,” and this elimination of Habricius’s species as 
something distinct is interesting. Further, his synonymy 
shows that he regarded Aubé and Stephens as wrong in their 
species. 
Bach’s remarks are of interest mainly because of what he 
says as to the habitat of elegans. He describes depressus as 
very rare, while elegans, he says, occurs in the salt lake at 
Hisleben, a statement which agrees with Schaum’s observa- 
tions at Siilldorf and Stassfurth, also in Saxony but a little 
farther north. For a species which elsewhere occurs in lakes 
and rivers this habitat is remarkable, but we find other 
Hydradephaga and Hydrophilide showing similar pecu- 
liarities—in fact, several at least of our brackish-water beetles 
are freshwater species in the Mediterranean district. 
Seidlitz for the first time gets off the beaten track, and 
about ninety years after the discovery of the two species finds 
reliable characters upon which they may be separated. He 
refers to the different forms of the two insects, mentioning 
the thorax, and he also mentions the difference in form and 
size of the anterior tarsal claws of the males ; and from his 
description, which has been enlarged upon by Ganglbauer, 
I regard our northern species as his “ depressus”’ and our 
common one as his elegans. 
In a footnote (1886, p. 57) he states that Sturm was the 
first to separate the two species, and that the earlier writings 
of Panzer and Illiger refer to depressus. Undoubtedly Sturm 
is the first author to refer to both and to describe them as 
separate species, but I can find no evidence for the statement 
as to Panzer and Illiger. So far as colour is of any value as 
a discriminating character, it is quite evident that Panzer 
is referring to lighter-coloured specimens than Fabricius, and 
from the chain of evidence which I have outlined I regard 
elegans as his species. 
Habitat and Britannic Distribution. 
So far as habitat is concerned, D. elegans is a river and 
loch species in our islands, whereas, omitting Ireland, which 
