MOTIONS OF INSECTS. 



231 



horizontally, it bends its body alternately to the right and 

 left, contracting itself into the form of the letter S ; and then 

 extending itself again into a straight line, by these alternate 

 movements it makes its way slowly in the water. 1 



I have dwelt longer upon the apodous larva?, or those that 

 are without what may be called proper legs, analogous to 

 those of perfect insects, because the absence of these ordinary 

 instruments of motion is in numbers of them supplied in a way 

 so remarkable and so worthy to be known ; and because in 

 them the wisdom of the Creator is so conspicuously, or, I 

 should rather say, so strikingly manifested, since it is, doubt- 

 less, equally conspicuous in the ordinary routine of nature. 

 But aberrations from her general laws, and modes, and instru- 

 ments of action, often of rare occurrence, impress us more 

 forcibly than any thing that falls under our daily observation. 



I come now to pedate larvae, or those that move by means 

 of proper or articulate legs. These legs (generally six in 

 number, and attached to the underside of the three first seg- 

 ments 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), of 

 perfect insects, the legs of which they include. Cuvier, speak- 

 ing of Coleoptera and some Neuroptera, 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 Lamellicoruia, Dytisci, Silphce, Staphylini, 

 Cicindelce, and Gyrini, &c. amongst coleopterous larvae; and 

 the Trichoptera, as well as the Libellulina and Ephemerina, 

 amongst Cuvier's Neuroptera, — have these joints, and in many 

 the last terminates in a double claw. 2 In some coleopterous 

 genera the tarsus seems absent or obsolete. The larva of the 

 lady-bird (Coccinella) affords an example of the former kind, 

 and that of Chrysomela of the latter. 3 These joints are very 

 visible in the legs of caterpillars of Lepidoptera, and their tar- 



1 Swamm. Bibl. Nat. Ed. Hill, ii. 44. b. 47. a. 



2 For examples of larvae having these joints, see De Geer, iv. 289. t. xiii. 

 f. 20. t. xv. f. 14. ii. t. xii. f. 3. t. xvi. f. 5, 6. t. xix. f. 4, &c. 



3 Ibid. v. t. xi. f. 11. t. ix. f. 9. o. 



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