308 SOCIAL LIFE IN THE INSECT WORLD 



With the purchase thus obtained the insect rises a 

 little and reaches the wire gauze, the equivalent of the 

 twig which would be chosen for the site of the trans- 

 formation in the open fields. It holds to this with the 

 four anterior limbs. Then the tip of the abdomen is 

 finally liberated, and suddenly, shaken by the final 

 struggle, the empty skin falls to the ground. 



This fall is interesting, and reminds me of the per- 

 sistence with which the empty husk of the Cigale braves 

 the winds of winter, without falling from its supporting 

 twig. The transfiguration of the locust takes place very 

 much as does that of the Cigale. How is it then that the 

 acridian trusts to a hold so easily broken ? 



The talons of the skin hold firmly so long as the 

 labour of escape continues, although one would expect 

 it to shake the firmest grip ; yet they yield at the slightest 

 shock when the labour is terminated. There is evidently 

 a condition of highly unstable equilibrium ; showing 

 once more with what delicate precision the insect 

 escapes from its sheath. 



For want of a better term I said *' escape." But the 

 word is ill chosen ; for it implies a certain amount of 

 violence, and no violence must be employed, on account 

 of the instability of equilibrium already mentioned. 

 If the insect, shaken by a sudden effort, were to lose 

 its hold, it would be all up with it. It would slowly 

 shrivel on the spot ; or at best its wings, unable to 

 expand, would remain as miserable scraps of tissue. The 

 locust does not tear itself away from its sheath ; it 

 delicately insinuates itself out of it — I had almost said 

 flows. It is as though it were expelled by a gentle 

 pressure. 



