The Glow- Worm and Other Beetles 



dark alike, neither more rapidly nor more 

 slowly and without difference in the tints. 



This negative result was easy to foresee. 

 The Buprestis emerging from the depths of 

 the trunk in which he has spent his larval 

 life; the Geotrupes and the Phanaeus leav- 

 ing their natal burrows possess their final 

 adornments, which will not become richer in 

 the rays of the sun, at the time when they 

 make their appearance in the open air. The 

 insect does not claim the assistance of the 

 light for its colour chemistry, not even the 

 Cicada, 1 who bursts her larval scabbard and 

 changes from pale green to brown as easily 

 in the darkness of my apparatus as in the 

 sunlight, in the usual manner. 



The chromatics of the insect, having as its 

 basis the urinary waste products, might well 

 be found in various animals of a higher or- 

 der. We know of at least one example. 

 The pigment of a small American lizard is 

 converted into uric acid under the prolonged 

 action of boiling hydrochloric acid. 2 This 

 cannot be an isolated instance ; and there is 

 reason to believe that the reptilian class 



1 Cf. The Life of the Grasshopper: chaps, i. to v. 

 Translator's Note. 



2 A. B. Griffiths, Transactions of the Academic des sci- 

 ences, 26 November, 1894. Author's Note. 



292 



