Genera of the Cossonidce. 589 



at Madeira, and the habits of which seem to be very 

 similar to those of Pentarthrum and Amaurorrhinus ; and 

 it is only now that I have been enabled to identify it, 

 through the examination of more extensive material, with 

 the European Rhyncolus culinaris, 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- 

 thrum 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 Cossonida (outside the very anomalous subfamily 

 Onycholipides) in which the funiculusis composed of only 

 six articulations ; and it is further remarkable for its 

 rostrum being short and narrowly subtriangular, for its 

 antennas 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 

 coxse being subcontiguous. As in Stereocorynes and 

 Tomolips, its antennas 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 Japan, 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 



