Deronectes depressus, Fab., and elegans, Panzer. 299 
type might exist in this country. Fabricius, in his ‘ Entomo- 
logia Systematica,’ frequently mentions where his type- 
specimens are to be found, but in the case of “ Dytiscus 
depressus”’ le gives no such information; and an examination 
of the Banksian Collection in the Natural History Museum 
and of Graham Kerr’s published list of Fabrician types 
in the Glaszow University Museum failed to discover its 
location. It is presumably in Copenhagen or some other 
Scandinavian museum if it is still in existence. 
As to Panzer’s type, I could get no information, and in the 
absence of the types I had to fall back upon the literature. I 
therefore started with Fabricius’s Ent. Syst., and examined 
most of the important works from 1792 up to the present 
time, and I have looked up more than forty references in the 
course of this examination. Two points have struck me 
during this part of the work: one is the exceeding vagueness 
of the original descriptions, which give only colour-characters 
for the recognition of the species, and tlie other is that, where 
subsequent authors have treated depressus and elegans as 
distinct species, they have mostly shown an extraordinary 
lack of originality, relying, like their predece-sors, mainly 
upon colour-characters and merely varying the words of the 
original descriptions. 
T have included at the end of this paper a bibliography of 
the works I have looked up, with, in each case, a short note 
as to the view taken by the author, but a short résumé of 
some of the more important works may be of interest. 
Fabricius’s original description was published in 1792 and 
that of Panzer about 1793—Paykull, Llliger, and Marsham 
following in order of date. ‘The first only refers to Fabricius’s 
species, without giving any indication as to whether he knew 
elegans. Illiger describes the colouring of Panzer’s species, 
and then says “ the D. depressus appears to be closely related 
to this species,” showing that he only knew the latter from a 
description. 
How Marsham identified our common British species as 
elegans we have no means of knowing, but we can assume 
that either he did not know depressus, which seems probable, 
or that he regarded it as distinct from Panzer’s species. 
Duftschmidt seems to have been the first to regard 
“elegans” as a synonym of “ depressus,” though the remark 
he makes suggests that he possibly had the latter, since he 
mentions that whereas Panzer and Illiger describe their 
species as having the underside rusty red, his specimens have 
that part black. 
