OF THE ANTENNÆ OF INSECTS. 387 
terminal joint, sen is more elongated than the rest: they consist of the smaller and 
larger sort, as in Silpha; but arranged in a manner very peculiar, and confined to the 
lower half of the terminal joint. The smaller forms are disposed in groups of from six to 
sixteen in each. The groups are diamond-shaped, with a row of hairs between them: at 
the angle are occasionally found the larger organs, as in Silpha, as also a few scattered on 
the upper half of the joint. Their covering-in membrane, however, is not so conical. 
The diameter of each of the small organs is 5-55 inch. (See C. fig. 1.) 
In Goerius olens the organs are distributed thickly over the surface, rather more fre- 
quently than the hairs, and show their sacculated nature very well (D. aa). 
In Carabus there are eleven joints in the antenna ; only the last five possess the organs. 
They are not so numerous as those I have described before, and are principally placed on 
one side of the antenna, as shown in E. 
In all the species examined of this genus, I have found the closing-in membrane raised 
considerably above the surface-level, more so than in Silpha, and having six or eight ridges 
running from apex to base, as is shown in E. figs. 2, 3. The greatest diameter of the sac 
is +550 inch, while that of the closing-in membrane at the surface is 3557 inch. The 
Section, fig. 1, shows the form of the sacs and closing-in membrane. 
In six species of Ælater which I have examined, I find the same conditions, namely : 
chiefly on the serre of the joints, generally in front of the base of the hairs, are small 
sacs about 3357 inch in diameter, as is shown in F. figs. 1, 20 &b. The closing-in mem- 
brane is slightly raised above the surface; and on the apex are from three to six, generally 
four, small papillæ or tubercles, as is shown in F. fig. 2 0, & fig. 3. 
In Strangelia elongata these sacs are very numerous, disposed over eight of the twelve 
joints, and becoming larger and more frequent towards the apex. Theyare generally situ- 
ated in front, or near the roots of the hairs; and their closing-in membrane is much smaller 
than the diameter of the sacs beneath. These sacs vary much in size, being from 37; to 
sovo inch in diameter. The larger sort seem convoluted, or two- or three-chambered. 
The antennæ of the Musk Beetle (Aromia meer v = similar ; and the same | 
description will apply, except that the sacs are larger t wem 
In iie iab: the didi lamellæ are furnished with sacs, which are placed close 
together, and are found on both sides of the middle one only, and on that side of the first 
and third which is in contact with the middle one. ng ie 
In the antenna of Dynastes Hercules the sacs are very — P and the un 
membrane well marked, their diameter being about 3760 inch. They are = seco 
same parts of the lamellæ as in Cetonia aurata. In consequence of the sacs no 
| from the inner aspect of 
through the whole thickness of the antenna-wall, a tube passes "rom Chus dho 
each to connect it with the interior of the lamella: towards the margin of : : 
‘thin the thickness of the integument ; 
form is modified, the sac being placed halfway wit : smaller one extend- 
and there is not only a tube connecting it with the interior, but also penes csse 
ing to the outer surface (H. figs. 1,2). Numerous depressions, in . 
: i I have hitherto 
cavities, ate to be found in the antenna; and in all the Lam ET gre thus common 
examined, the sacs are situated on all portions of these depressions, 
to them. | 3E2 
