344 



INSECT TRANSFORMATIONS. 



pared for swarming immediately, if there be a ne- 

 cessity for it, or that the young queen may be in a 

 condition to drive out her royal mother, and take her 

 place if there be occasion."* 



It does not appear, however, that Swammerdam 

 proved by dissection the simultaneous existence of 

 air and blood-vessels in the wings, but merely infers 

 this, as Reaumur afterwards did, from the phenomena. 

 But Jurine has since actually demonstrated that every 

 vein {nervure) of a wing contains an air-tube, which 

 originates in the windpipe, and follows in a serpen- 

 tine form, w'ithout filling, every branchlet of the 

 nervures. Those who have not paid attention to this 

 curious subject have little conception of the great 

 diversity of forms which are exhibited by the branch- 

 ings of these nervures, not only in diiferent orders, 

 but even in different species of insects. They differ, 

 indeed, as much in this respect as the leaves of plants 

 do in their mode of veining. 



Wings of insects :— a, wing of a beetle ; h, wing of an earwig ; 

 c, wing of a saw fly; d, wing of a crane-fly ; e, wing of a com- 

 mon fly {Musca) ; f, wing of a midge {Psychuda). 



* Swammerdam, i. 187. 



