EXTERNAL ANATOMY OF INSECTS. 511 
see that it is merely the base of the scape swelled out 
into aspherical or other- kindred form*; and often 
marked, as in the Cicindelide, with impressed points: as 
it is the piece by which the antenna moves in its socket, 
this form of a rotwla was doubtless given for its more 
ready motion in all directions. This structure is prin- 
cipally conspicuous in the Coleoptera and Hymenoptera 
Orders : in the others the base is not so distinguished 
from the rest of the scape. If you carefully extract the 
antennze of a beetle, say a Copris or Lamia, and exa- 
mine its base or bottom, you will find that it is open for 
the transmission of muscles and nerves; that in its up- 
per margin it has a deep notch or sinus, on each side of 
which is a smaller notch; and that all round the margin, 
which is very lubricous, a membranous ligament is at- 
tached, by which it was affixed in the torulus. Its arti- 
culation, therefore, seems of a mixed kind, like that of 
most other organs and parts of insects, partaking of the 
ligamentous, ginglymous, and ball and socket. In the 
Orthoptera, Hemiptera, &c. the articulation seems more 
purely ligamentous. 
With regard to their swbstance—these organs are re- 
gulated, in some degree, by the nature of the integu- 
ment of the animal of which they are appendages; in 
the softer insects being of a softer substance than they 
are in hard ones. ‘The vertex of the joints, where they 
receive the succeeding one, appears in many cases to be 
softer than the rest of it, and especially towards the apex, 
* Prate XII. Fie. 9.1’. This circumstance was very recently 
discovered; which will account for this plate not being quite correct 
in this respect, the bulb being represented as a distinct joint in 
Fic. 6, 10, 26. 
