STATES OF INSECTS. 135 



i. The prologs of almost all Lepidopterous larvae are 

 furnished with a set of minute slender horny hooks, crot- 

 chets, or claws, of different lengths, somewhat resem- 

 bling fish-hooks ; which either partially or wholly sur- 

 round the apex like a pallisade. 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 a . Claws nearly similar 

 are found on the prolegs of some Dipterous larva? b , 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 go its hold, it begins to draw in the skin of the sole, 



a The claws or crotchets, though general, are not universal, in 

 Lepidopterous larva?. An exception is furnished to the rule by the 

 singular limaciform ones of Hepialus 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 Goeze, Naturf. xv. 37 — 48, (who 

 has satisfactorily ascertained that it is the true larva of a Tinea of 

 Linne, 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. b Plate XXIV, Fig. 7. See also below, p. 137- 



