STATES OF INSECTS. (Larva.) 135 
surround the apex like a palisade. By means of these 
claws, of which there are from forty to sixty in each 
proleg, a short and a long one arranged alternately, the 
insect is enabled to cling to smooth surfaces, to grasp 
the smallest twigs to which the legs could not possibly 
adhere: a circumstance which the flexible nature of 
the prolegs greatly facilitates*. Claws nearly similar 
are found on the prolegs of some Dipterous larvee », but 
not in any of those of the other orders. These last, how- 
ever, are seldom either so numerous, or arranged in 
the same manner, as in caterpillars. When the sole of 
the foot is open, the claws with which it is more or less 
surrounded are turned outwards, and are in a situation 
to lay hold of any surface; but when the animal wishes 
to let goits hold, it begins to draw in the skin of the sole, 
and in proportion as this is retracted, the claws turn 
their points inwards, so as not to impede its motion °. 
The prolegs with claws may be further divided into 
four different kinds. 
2 The claws or crochets, though general, are not universal, in 
Lepidopterous larvze. An exception is furnished to the rule by the 
singular dimaciform ones of Hepiolus Testudo and Asellus of Fabricius, 
two moths forming Haworth’s genus Apoda, which have no distinct 
prolegs, but in their stead a number of small transparent shining tu- 
bercles without claws. The larva also of one of the subcutaneous 
moths first discovered by De Geer in the leaves of the rose (i. 446), 
but whose history is fully given by Gceze, Naturf. xv. 37—48, (who 
has satisfactorily ascertained that it is the true larva of a Tinea of 
Linné, but of a different habit from that of most subcutaneous ones), 
has no true legs, and eighteen prolegs without any claws. Another 
subcutaneous larva, for the history of which we are indebted to 
M. Godeheu de Riville, is according to him entirely deprived of legs 
of any kind (Bonnet ix. 196—.); as is another of the same tribe that 
feeds on the poplar, an account of which is given by Goeze Naturf. 
xiv. 105. » Prats XXIII. Fic. 7. See also below, p. 137. 
* Lyonnet Anatom. 84. ¢. iii. f. 11, 12. 
