The Glow-Worm and Other Beetles 



may be, smooth or hairy, living or inanimate. 

 This done, they behave very differently, ac- 

 cording as they have chanced to invade the 

 body of an insect or some other object. In 

 the first case, on a downy Fly or Butterfly, 

 on a smooth-skinned Spider or Beetle, the 

 larvae remain motionless after reaching the 

 point which suits them. Their instinctive 

 desire is therefore satisfied. In the second 

 case, in the midst of the nap of cloth or vel- 

 vet, or the filaments of cotton, or the flock of 

 the everlasting, or, lastly, on the smooth 

 surface of a leaf or a straw, they betray the 

 knowledge of their mistake by their continual 

 coming and going, by their efforts to return 

 to the flower imprudently abandoned. 



How then do they recognize the nature of 

 the object to which they have just moved? 

 How is it that this object, whatever the qua- 

 lity of its surface, will sometimes suit them 

 and sometimes not? Do they judge their 

 new lodging by sight? But then no mistake 

 would be possible ; the sense of sight would 

 tell them at the outset whether the object 

 within reach was suitable or not; and emigra- 

 tion would or would not take place accord- 

 ing to its decision. And then how can we 

 suppose that, buried in the dense thicket of 

 a pellet of cotton-wool or in the fleece of an 



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