The Mason-Wasps 



able imitation, in order to put their per- 

 secutors off. The simple creatures! It 

 never entered their heads to protect them- 

 selves by mimesis! We will not blame 

 them; it is not their fault. They are what 

 they are; and no bird's beak will make them 

 change their costume. 



The Chrysomela's defensive fluid has a 

 look of essential oil : it discolours paper with 

 a semitransparent stain which disappears by 

 evaporation. Its colour is opalescent; its 

 flavour is horrible; its odour is excessively 

 strong and may be compared with that 

 of the nitrobenzene of our laboratories. 

 Were it not that I lack the leisure and the 

 apparatus, I would gladly undertake a little 

 research-work into this singular product of 

 animal chemistry, which, I think, is quite as 

 worthy of exploration by our tests as the 

 milky exudations of the Salamander or the 

 Toad. Meanwhile I commend the problem 

 to the chemists. 



In addition to the eighteen flasks of es- 

 sential oil, the grub possesses yet another 

 protective device, which is at once defensive 

 and locomotory. The end of the intestine 

 expands, at the insect's pleasure, into a 

 large amber-coloured pimple, whence oozes 

 a colourless or very pale-yellow liquid. I 

 196 



