Cossonidce of Jajoan. 15 
The structural characters of this narrow and linear little 
Cossonid shew it to be a true Pentarthrum, — its 5-jointed 
funiculus, medially-inserted antennae, and its developed 
eyes and scutellum, added to its colour, outline, and sciilp- 
ture, being in entire accordance with the two hitherto de- 
scribed members of that group. I say " two," because a 
more careful examination of the unique weevil from St. 
Helena, which I enunciated nearly three years ago under 
the title of Pentarthrum suhccBcum* has recently con- 
vinced me that it is the type of a new genus allied 
to Mesoxeniis (well characterized not only by its ob- 
solete eyes and scutellum and its more apically-im- 
planted antennae, but likewise by its convex, largely- 
developed pro thorax and general aspect and sculpture), 
and not an " aberrant Pentarthrum.''^ So that, up to the 
present date, only two veritable Pentarthra had been 
brought to light, — namely, the English P. HiMoni (for 
the reception of which, in 1854, I originally proposed the 
genus), and the P. cylindricum, which was detected by 
the late Mr. Bewicke in the island of Ascension : and 
I need scarcely add therefore that a third representative, 
from Japan, and one so remarkably well defined, is a fact 
of considerable importance geographically. As elsewhere 
stated, however, there is a peculiarity about the modus 
Vivendi of the Pentarthra which renders it highly probable 
that the group will be found eventually to have a very wide 
range, — their habits being, apparently, to follow in the 
wake of civilization by attaching themselves to old planks, 
boards, rafters, casks, &c., on the rotten (and often tinder- 
like) wood of which they more especially subsist. Thus 
the English P. Huttoni was obtained originally amongst 
logs of wood which had been loug laid up in an out-house, 
and it was subsequently met with in a decayed cask near 
Plymouth, and by myself in portions of an ancient plank 
adjoining my house and conservatory at Teignmouth ; and, 
in like manner, the P. cylindricum, at Ascension, was 
captured abundantly by Mr. Bewicke in the broken-up 
wood of a worn-out box in which plants had been culti- 
vated. It is consequently quite in accordance with what 
I may perhaps be permitted to call their generic mode of 
life that the present Pentarthrum should have been dis- 
covered by Mr. Lewis, in Japan, " by beating the straw 
roofing of old cottages near Nagasaki;" and I may ftirther 
remark that I believe him to be perfectly correct when he 
* Vide Ann. Nat. Hist. (1869). 
