Mr. T. V. WoUaston on the Goleoptera of St. Helena. 411 



culo 5-articiilato, art° 1""° fere obtriangulari, 2^° paulominore et 

 sequentibus (subaequalibus) vix longiore ; tarsis gracilibus, art° 3*'° 

 minus dilatato, prsecedentibus vix latiore, et vix bilobo. 

 Long, Corp. lin. 1^. 



The unique example from which 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. Huttoni from the west of Eng- 

 land and the P. cylindricum which was found by Mr. 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 3Iesoxenus, of the Madeiran and 

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

 in common with Pentarthrum than with Mesoxenus 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 Pen- 

 tarthrum with 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 their 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. suhccecum is darker and less deeply sculptured than 

 either the P. Huttoni or the cylindricum^ 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. Huttoni, 

 in which 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 

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

 geographical point of view, extremely interesting, the various 

 Atlantic islands having already supplied so many anomalous 

 additions (both in genera and species) to these immediate 

 Cossonideous groups. 



