Genera of the Cossonidce. 433 



Notiomimetides, in which the visual organs are so far 

 reduced in dimensions, and so rudimentary in character, as 

 to be emphatically obsolete, 



Into the question of the geographical distribution I need 

 not now enter, for a glance at the systematic catalogue 

 will suffice to shew approximately what the ranges are of 

 the several types. It is curious however to note how large 

 a proportion of the latter, which have hitherto been brought 

 to light, possess insular habitats ; and, if we except the 

 great and almost cosmopolitan genus Cos s onus, it would 

 seem as if islands afforded conditions more peculiarly 

 favourable for the modes of life of the members of the 

 present family. And this completely accords with my 

 own experience in the sub- African archipelagos, no island 

 appearing to be too minute for the modus vivendi of the 

 Cossonids. In the Maderian and Canarian groups there 

 is scarcely any fact more distinctly observable, where 

 every detached rock is tenanted by some one represen- 

 tative, or more, of this particular department. Nor are 

 trees and shrubs (which seldom flourish in localities thus 

 weather-beaten and exposed) by any means essential for 

 their support, the pithy stems of the ordinary plants 

 being amply sufficient to sustain them ; and I have 

 frequently found the stalks of dead Thistles and Umbel- 

 lifers to be perforated through-and-through by their 

 ravages. In our own country the Cossonids would seem 

 to play a very insignificant part amongst the Coleopterous 

 population, only nine members having hitherto been re- 

 corded ; whereas at the Canaries (made up, as they are, 

 of so many islands and islets) I have myself met with no 

 less than fourteen, and at the Madeiras (which present a 

 considerably smaller area) with nineteen ; whilst even in 

 the little island of St. Helena (the geographical base of 

 which does not exceed that of the Isle of Wight) as many 

 as fourteen have already been noted, and these I have good 

 reason to suspect represent but an instalment of its whole 

 Cossonideous fauna. The British members of our present 

 family are as follows : Pentarthrum Iluttoni, Woll. 

 (= Rhyncolus Hervei, Allard) ; Phlceophagus spadix, 

 Hbst., and aneopiceus, Bohm. ; Rhopalomesites Tardii, 

 Curt.; Cossonus ferrugineus, Clairv. ; Rhyncolus ater, 

 Linn. (= chloropus, Fab.), cylindrirostris, Oliv. (= lig- 

 narius, Mshm.), and gracilis, Rosenh. ; and Stereocorynes 

 truncorum, Germ. 



