The Larva and the Nymph 



ness, realized the natural conditions of the 

 nymphs and served me as a standard of com- 

 parison, while the others, hung against a 

 white wall, received a strong diffused light 

 throughout the day. Under these diametric- 

 ally opposed conditions, the evolution of the 

 colours remained absolutely uniform in both 

 cases, or, if there were some slight dis- 

 crepancies, these were to the disadvantage of 

 the pupas exposed to the light. It is, there- 

 fore, exactly the reverse of what happens in 

 the case of plants: light does not affect the 

 colouring of insects, does not even accelerate 

 the process; and this must be so, because, in 

 the species which are the most brilliant in 

 colouring, the Buprestes and Ground-beetles, 

 for instance, the wondrous hues which one 

 would imagine to be stolen from a sunbeam 

 are really elaborated in the dusky bowels of 

 the earth or deep down in the decaying trunk 

 of some venerable tree. 



The first outlines of colour show on the 

 eyes, whose faceted cornea changes success- 

 ively from white to fawn, next to slate-grey, 

 lastly to black. The simple eyes at the top 

 of the forehead, the ocelli, share in this 

 colouring, in their turn, before the rest of the 

 body has yet lost any of its neutral, white 

 107 



