Mr. T. V. Wollaston on the Coleoptera of St. Helena. 411 



ciilo 5-articulato, art° 1""° fere obtriangulari, 2**° paiilo minora et 

 scqiieutibus (subacqualibus) vix longiore ; tarsis gracilibus, art" 3"° 

 miniis dilatato, proecedentibus vix latiore, et vix bilobo. 

 Long. corj). lin, li. 



The unique example from wliicli the above diagnosis has 

 been drawn out, and which was captured at St. Helena by 

 Mr. Melliss, possesses so unmistakable an affinity (in its five- 

 jointed funiculus and the general contour of its narrow, sub- 

 cylindrical, sculptured body) with the genus Pentarthrum (as 

 known hitherto through the P. Ihdtoni from the west of Eng- 

 land and the P. cijUndricum which was found by jMr. Bewicke 

 at Ascension) that I cannot persuade myself that it should be 

 separated therefrom, even whilst equally aware that its obso- 

 lete eyes and scutellum would, of themselves, tend to affiliate it 

 rather with the little group Mesoxenus, of the Madeiran and 

 Canarian archipelagos. Yet I feel so satisfied that it has more 

 in common \w'i^\ Pentarthrum tlian with Mcsoxemis that I have 

 preferred assigning it to the former, even should my doing so 

 necessitate the diagnosis of that genus being so far widened as 

 to embrace representatives in which (like the Mesoxeni) the 

 eyes and scutellum are obsolete. Perhaps, in reality, however, 

 it will be found desirable, in the end, to treat it as the type of 

 a yet additional group — combining the external aspect of Peyi- 

 tarthrum Avith the escutellate sub-eyeless body of Mesoxenus ; 

 but as these little Cossonideous assemblages are already per- 

 haps somewhat too numerous, I will not at present add an- 

 other to ihnxx number, but will be content to cite the very in- 

 teresting weevil now before me as an aberrant Pentarthrum 

 in which there are no traces of a visible scutellum, and none 

 also (beyond the merest rudimentary punctiform specks — of 

 the true existence of which I can scarcely satisfy myself, even 

 beneath the microscope) of eyes. 



The P. suhc(vcum is darker and less deeply sculptured than 

 either the P. Ilattoni or the cijUndricum, and it is, if anything, 

 perhaps a trifle narrower and smaller than even the latter ; 

 but its prothorax is less strictly conical than in the Ascension 

 species, assuming more the outline of the English P. Iluttoni, 

 in whicli the sides are more rounded, and the widest part is 

 (not at the extreme base, but) a little behind the middle. In 

 the structure and shortness of its limbs and rostrum it recedes 

 from the Mesoxeni, and is in exact accordance with the true 

 Pentarfhra. In any case, its discovery at St. Helena is, in a 

 geographical point of view, extremely interesting, the various 

 Atlantic islands having already supjjlied so many anomalous 

 additions (both in genera and species) to these iuunediate 

 Cossonideous groups. 



