MADEIRAN COLEOPTERA, 205 
the head, and rather deeper and more numerous on the elytra than 
elsewhere) intermixed, and almost opake. Head black, or piceous- 
black; with the anterior angles (beneath which the antenne are 
inserted) a little raised, but rounded-off; with an oblique groove 
extending backwards from either anterior angle to the hinder 
part of the forehead,—the groove being shallow (and sometimes 
evanescent) in the centre, but deep and abruptly terminated 
behind, where there is a piceous (or yellowish-piceous) ocellus 
immediately within it. Prothorax transverse-quadrate, and a little 
narrowed posteriorly ; rufo-ferruginous; and with a shallow, sub- 
obsolete longitudinal fovea on either side of its hinder disk. 
Elytra short, and testaceous, with their apical portion gradually 
(and more or less darkly) clouded, or blackened ; and generally 
with their scutellary region, also, slightly so. Abdomen unequally 
brownish-piceous. Antenne shorter than in the last species, and 
more distinctly clavated than in either it or the O. granulatum ; 
the club, which is composed of the last six joints, dark fusco- 
piceous: the rest of the antenne, together with the legs, rufo- 
testaceous. 
The very interesting Omalium from which the above description 
has been compiled would seem to occur peculiarly (so far as I have 
hitherto observed) beneath the bark of the gigantic Huphorbia 
mellifera,—under which circumstances I took it (or, rather, might 
have taken it) in considerable abundance, during the summer of 
1855, in the upland region of the Fanal. In conjunction indeed 
with Aphanarthrum and Mesites Euphorbic, it is completely de- 
stroying the noble Euphorbias for which that elevated district is so 
famous; and I may add that the same fact was noticed by Mr. 
Mason, during his recent encampment on the selfsame spot. 
Although very distinct specifically, it belongs to exactly the same 
structural type as the other two Madeiran Omalia; and concerning 
its general affinities, Mr. Janson (to whom I latcly submitted it for 
inspection) makes the following remark :—‘“ The peculiar form of its 
antenne (presenting an elongate, six-jointed club) places this species 
in intimate connexion with the 0. planwm, from which, however, it 
differs abundantly,—in colour, in its narrower form, longer elytra, 
sparsely punctured abdomen, more robust antenne, small, alutaceous 
and almost impunctate head; and in its narrow and densely aluta- 
ceous thorax (with exceedingly shallow punctures thinly strewn over 
its surface), which has moreover two shallow post-dorsal impres- 
sions, and no appearance of the rounded fovez which are so evident 
on the anterior margin in that insect.” Its somewhat unusually 
clavated antenn (the club of which, however, is better defined than 
it would otherwise appear, through its being darkly coloured) has 
suggested its specific name. 
