460 APPENDIX. 
to the American species : ‘‘ Considerable stress has been laid on the fact 
as to whether the base of the thorax has a marginal line, but as far as 
our species are known it exists in all, but varies in the sharpness of its 
definition.” 
The first two sub-genera, mentioned in Kuwert’s paper, are not repre- 
sented in Britain: these are Mrcilus, Schiddte (containing a single 
species, MM. murinus, Kies.) and Phyrites, Schiédte (containing a single 
species, P. aureolus, Schiddte) ; the former is distinguished by the shape 
of the scutellum (which is punctiform and subtransverse) and the latter 
by having the third joint of the antennz small and the fourth forming 
with the following a uniform club, whereas in Heterocerus and Tenhe- 
tocerus the third and fourth joints are both small. 
Kiesenwetter appears to have been the first who attempted to mono- 
graph the species, and he divided them chiefly on colour and sculpture, 
both of which are very misleading characters, as both vary ccnsiderably 
in different specimens of the same species ; Schiddte in 1866 attempted 
a division on obscure antennal characters ; in 1872, however, Mulsant 
and Rey observed that in certain species the elevated curved line on the 
first ventral segment extended from the front angle by a broad curve 
towards the middle of the posterior edge of the segment and there ter- 
minated, while in others the line continued the curve forward towards the 
inner edge of the cox; these lines are apparently stridulating organs, 
and the genus is divided by Dr. Horn on this character as follows :— 
Stridulating ridge of first ventral segment incomplete, 
i.e. extending from the front angle ina curved line 
merely to the posterior border of the segment . . HETEROCERUS, i. sp. 
Stridulating ridge of first ventral segment complete, 
i.e. forming nearly a semicircle from the front 
angle to the posterior border, then recurving to the 
Inner:cOxal Porderien se ste ls ie re ce ee ee oo LIT TORIMUSS Des*Gocas: 
The latter division was originally wrongly named Augyles, which was 
the name applied by Schiddte to quite a different division, founded, as 
above-mentioned, on obscure antennal characters, 
As far as our fauna is concerned the characters depending on these 
stridulating organs are not of much practical use, as the sub-genus Littori- 
mus only contains two species, H. britannicus and H. sericans, and it is 
doubtful whether the latter species can really be regarded as indigenous ; 
it seems, therefore, that we must to a certain extent fall back upon the 
character presented by the margination of the posterior angles of the 
thorax, in spite of its being often so unsatisfactory ; H. jlexuosus, 
JSemoralis, salinus v. rectus and arenarius will be found to present scarcely 
a trace of margins, whereas in the other species they are more or less 
distinctly visible. Dr. Sharp (Biol. Cent. Am. vol. i. pt. 2, p. 116) 
makes use of a character, which he has recently observed, and which may 
prove to be of considerable importance; in several of the American 
species there is an elevated line on the metasternum, which begins at 
the middle of the posterior border of the middle coxa, extending 
