STRUCTURES IMPLICATED IN METAMORPHOSIS. 1 9 



The joint in the legs of the perfect insect nearest the bod" 

 is called the hip or coxa, the next the thigh or femur ; then the 

 leg or tibia succeeds, and finally the many jointed tarsus with 

 its hooks. 



It has already been noticed that the larvae of many kinds of 

 insects are entirely destitute of legs and feet Thus the grubs of 

 the hornet, Vespa crabro, are legless; and yet the remarkably 



THE LEGLESS LARV^ OF THE BEE. NYMPHS OR PUP^ OF THE BEE. 



active limbs of the perfect insect have to be developed with all 

 their muscles and nerves during metamorphosis ; and the apodal 

 or legless condition of the larvae and pupae of the worker bees may 

 be understood by examining the engraving of them. 



The legs of insects, although true locomotive organs, are often 

 adapted to an infinitude of uses, and they are formed in numerous 

 shapes, and present innumerable special structural adaptations, so 



CATERPILLAR OF A "LOOPEK." 



that their study is really most interesting. Nevertheless, what- 

 ever may be the shape of the legs, their uses and functions, or 

 their condition of development, they are always formed upon a 

 definite plan, and have certain anatomical peculiarities. No better 

 idea of the extraordinary development of these locomotive organs 

 in the perfect insect, and of their rudimentary condition in the 

 larva and before metamorphosis has taken place, can be obtained 

 than by comparing the figures of the larva and adult Calosoina. 



The membranous feet are not fully developed in some caterpillars, 

 and the " loopers " in particular have rarely more than two instead 



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