APPENDIX. 461 
obliquely backward and joining the suture between the metasternum and 
its episternum ; it is possible that this may prove a good character with 
regard to some of our species. The males are, as Dr. Horn observes, in 
most cases easy to distinguish from the females; the head is larger and 
more prominent, the mandibles more slender and projecting, the labrum 
longer, and the clypeus retuse to a varying degree ; the thorax is at least 
as broad as the elytra, sometimes slightly broader, and not gradually 
narrowed to the front as in the female; at the same time it must be 
remembered that it is easy to regard the male as a separate species, an 
error which can only be avoided by capturing the species in the burrows, 
two, a male and a female, usually occupying one burrow, 
The British species have usually been considered to be eight in 
number; of these H. fossor, Kies. (rectus, Wat.) and H. arenarius, 
Kies., have been regarded as doubtful, and the generally recognized 
species, six in number, are H. femoralis, Kies., H. obsoletus, Curt., H. 
marginatus, F., H. levigatus, Panz., H. fusculus, Kies., and H. sericans, 
Panz. ; as far as 1 have been able to make out ZH. rectus, Wat., is an 
intermediate variety or species between 7. salinus and H. fossor ; 
H. arenarius must be regarded as a very doubtful species ; H. femoralis 
and H. flexuosus, which have usually been regarded as synonymous, 
must now be considered as distinct ; a new species, H. pulcheilus, Kies., 
must be added doubtfully before H. /fuseulus, and for LH. sericans a 
newly described species, H. britannicus, Kuw., must be substituted ; 
apparently we do not possess the true //. sericans, but the specimens 
which have been named for me by Herr Kuwert as H. britannicus 
appear to differ considerably, and I was at first inclined to think that 
part of them should be referred to an allied species, if not to H. sertcans, 
which may perhaps be found in our collections. The following then 
may be regarded as a provisional list of our species, as far as is at 
present known; they are given in the order in which they come in 
Herr Kuwert’s monograph :— 
Sub-gen, Heterocerus, 1. sp. 
flexuosus, Steph. (femoralis, Kies., pars). 
salinus, Kies., var. rectus, Wat. 
(arenarius, Kies. ? %) 
Jemoralis, Kies. 
Sub-gen. Teenhetocerus, Kuwert. 
marginatus, F. 
(sericans, Kies. ? 1) 
britannicus, Kuw. 
obsoletus, Curt. 
pulchellus, Kies. ? 
JSusculus, Kies. 
levigatus, Panz. 
H, flexuosus, Steph., and H. femoralis, K., are considered synony- 
mous in our catalogues; the latter insect is, however, smaller with the 
elytra rather shorter and the hinder indented cross markings situated a 
s.g. Littorimus, Des Gozis. 
