474 MOTIONS OF INSECTS. 



I come now to peJate \arvx, or those that move by means of proper or 

 articulate legs. Tliese legs (generally six in numbei^ and attached to the 

 underside of the three first segments of the body) vary in larvae of the 

 different orders : but they seem in most to have joints answering to the 

 hip (coxa); trochanter; thigh (femur); shank (tibia); foot (tarsus), o( 

 perfect insects, the legs of which they include. Cuvier, speaking of 

 Coleoptcra and some Nturoptcra, mentions only three joints. But many 

 in these orders (amongst which he included the Trichoptera) have the 

 joints I have enumerated. To name no more, the Lamellicornia, Dytisci, 

 Silpha, Staphylini, Cicindelce, and Gi/rini, &,c. amongst coleopterous 

 larvae ; and the Trichoptera, as well as the LibelluUna and Ephemerina, 

 amongst Cuvier's Ncuroptcra, — have these joints, and in many the last 

 terminates in a double claw.^ In some coleopterous genera the tarsus 

 seems absent or obsolete. The larva of the lady-bird (Coccinclla) affords 

 an example of the former kind, and that of Chrysomela of the latter.^ 

 These joints are very visible in the legs of caterpillars of Lepidoptera, 

 and their tarsus is armed with a single claw.^ The larvae that have these 

 legs walk with them sometimes very swiftly. In stepping they set forward 

 at the same time the anterior and posterior legs of one side, and the inter- 

 mediate one of the other ; and so alternately on each side. 



Pedate larva; are of two descriptions ; those that to perfect legs add 

 spurious ones with or without claws, and those that have only perfect legs. 

 I begin with the former — those that have both kinds of legs. But first 

 I must make a few remarks upon spurious legs. Because their muscles, 

 instead of the horny substance that protects them in perfect legs, are cov- 

 ered only by a soft membrane, they have been usually denominated mem- 

 branaceous legs ; since, however, they are temporary, vanishing altogether 

 when the insect arrives at its perfect state, — are merely used, for they do 

 not otherwise assist in this motion, as props to hinder its long body, when 

 it walks, from trailing on the ground ; to push against the plane of posi- 

 tion ; and, by means of their hooks or claws, to fix itself firmly to its sta- 

 tion when it feeds or reposes, — I shall therefore call them prolegs (^prope- 

 des'^). These organs consist of three or four folds, and are commonly 

 terminated, though not always, by a coronet or semicoronet of very minute 

 crooked claws or hooks. These claws, which sometimes amount to nearly 

 a hundred on one proleg, are alternately longer and shorter. They are 

 crooked at both ends, and are attached to the proleg by the back by means 

 of a membrane, which covers about two thirds of their length, leaving 

 their two extremities naked. Of these the upper one is sharp, and the 

 lower blunt. The sole, or part of the prolegs within the claws, is capable 

 of opening and shutting. When the animal walks, that they may not 

 impede its motion, it is shut, and the claws are laid flat with their points 

 inwards ; but when it wishes to fix itself, the sole is opened, becoming of 



> For examples of larvce having these joints, see De Geer, iv. 289. t. xiii. f. 20. t. iv. f. 

 14. ii. t. xii. f. 3. t. xvi. f. 5, H. t. xix. f. 4, &c. 



« Ibid. V. t. xi. f. 11. t. ix. f. 9. o. 



3 Lyonet, Tr. Annt. t. ill. f. 8. 



* l\Ir. W. S. Mat-Lcay, where quoted above, objects to this term ; bnt as the organs in 

 question are generally given to the animal to assist in its motions, and have been universallj 

 resarded as a kind of legs, ii was judged best, for the sake of distinction, to give ihem a 

 different name from perfect legs, and ai the same time oae that showed some affinity to 

 them. 



