THE METAMORPHOSIS. 443 



in the air, just as the gills are incessantly moved in the water ; the 

 insect, therefore, uses them for flight, as the former are used by larvae 

 for swimming. The endeavour of some naturalists to see arms in the 

 wings, and to indicate in their ribs the arm-bones with their joints and 

 inflexions, cannot therefore be justified. The wings present me with 

 no other resemblance to limbs than that they move and assist the pro- 

 gression of the creature. If this be the sole character of the arm or of 

 the leg, I will then admit that they are either arms or legs, but, other- 

 wise, certainly not. 



260 



But there is less doubt of the legs being analogous to the extremities ; 

 indeed, they have always been considered as such, and the entire leg 

 as well as its individual joints have been thence named. The first 

 question that suggests itself is Are the legs forms truly analogous to 

 the arms and legs of the vertebrata ? To this we may safely reply in 

 the affirmative, for these limbs are similarly situated, and often consist 

 of just as many, and sometimes, indeed, of more divisions. The similarity 

 of situation is shown above, where we have treated of the scapulae of 

 the vertebra representing the true scapulae ; we have there seen that 

 the legs hang attached to a distinct plate between the vertebra and the 

 sternum, which corresponds with the scapula or the ilium of the pelvis, 

 and that it is from this plate that the majority of muscles come, positive 

 facts which prove an important analogy. 



With respect to the division of the limbs, we always find in insects 

 at least five but never more than nine joints ; of these, the first and 

 third, with the smallest second, form a joint articulating upwards ; the 

 fourth with the third one articulating downwards ; the fifth with the 

 fourth one again articulating outwards ; the following joints, lastly, sit 

 where they present themselves upon the fifth, and take a straight 

 direction, and also participate in its motion, yet the entire foot can 

 bend downwards and again distend itself. A perfect conformity with 

 the anterior limbs of the superior animals has been supposed to be 

 found in these articulations. It has been endeavoured to explain the 

 first joint, the coxa of entomologists, as the humerus ; the second 

 smallest, as the separated olecranon, the analogue of the patella ; and 

 the third, the femur of entomologists, as the antibrachium ; the fourth 

 joint, the tibia of entomologists, would then be the carpus ; the fifth, 

 the metacarpus ; and the subsequent ones, the joints of the toes or 

 phalanges. This explanation becomes absolutely necessary, if the legs 



