Genera of the Cossonidce. 589 
at Madeira, and the habits of which seem to be very 
similar to those of Pentarthrum and Amaurorrhinns ; and 
it is only now that I liave been enabled to identify it, 
through the examination of more extensive material, with 
the European Rhyncolus cullnaris, of Germar, — a species 
which does not appear to be common in collections, or 
one which is very extensively known. Nevertheless I can 
detect no difference between the Madeiran insect and 
a type of the latter which has been communicated by 
Mr. Gray ; and I do not hesitate therefore in regarding 
them as identical. Yet the generic characters of Hexar- 
thritm remain clear and well defined, and afford another 
instance of the loose manner in which so many discordant 
forms have been associated with the Rhyncoli, and of the 
little care which appears to have been bestowed by certain 
Coleopterists on the structural features of their published 
species. 
So far as I am aware, Hexarthrum is the only member 
of the Cossonidce (outside the very anomalous subfamily 
Onycholipides) in which the funiculus is composed of only 
six articulations ; and it is fiirther remarkable for its 
rostrum being short and narrowly subtriangular, for its 
antennffi bring greatly abbreviated (even more so perhaps 
than in Stereocorynes), for its elytra being shortly cylindric, 
obtusely rounded behind, and subasperated (particularly 
as regards their posterior half), and for its four anterior 
coxai being subcontiguous. As in Stereocorynes and 
Tomolips, its antenna; are not only much reduced in length 
(especially the scape), but are likewise glabrous, and with 
the funiculus-joints very closely compacted together; 
nevertheless the club is more rounded, or less apically- 
truncate, than in those genera. Its prothorax also (which 
is unconstricted in front) is nearly unmargined at the 
base ; its first and second abdominal segments are divided 
by an unusually distinct line ; and its entire surface, 
although appearing quite bald, will be seen, when viewed 
beneath the microscope, to be very sparingly besprinkled 
(which is not the case in Stereocorynes and Tomolips^ with 
a short and most minute pubescence. 
I may state that a Hexarthrum has been detected 
lately by Mr. G. Lewis in Ja])an, closely allied to (but 
nevertheless unquestionably differing from) the European 
and Madeiran H. culinare ; and also that the European 
Rhyncolus submuricatus, Bohm., appears, if I may trust 
an example now before me from the collection of John 
T T 2 
