A TOAD WITH WARNING COLOURS 111 



from Monte Video, Nov. 24, 1832: 'As for 

 one little toad, I hope it may be new, that it 

 may be christened "diabolicus". Milton must 

 allude to this very individual when he talks of 

 " squat like a toad " ; its colours are by Werner 

 [Nomenclature of Colours, 1821] ink black, vermi- 

 lion red and buff orange.' ^ In the Journal of 

 Researches ^ its colours are described as follows : 

 *If we imagine, first, that it had been steeped 

 in the blackest ink, and then, when dry, allowed 

 to crawl over a board, freshly painted with the 

 brightest vermilion, so as to colour the soles of 

 its feet and parts of its stomach, a good idea 

 of its appearance will be gained.' 'Instead of 

 being nocturnal in its habits, as other toads are, 

 and living in damp obscure recesses, it crawls 

 during the heat of the day about the dry sand- 

 hUlocks and arid plains, . . . ' The appearance 

 and habits recall T. Belt's well-known description 

 of the conspicuous little Nicaraguan frog which 

 he found to be distasteful to a duck.^ 



The recognition of the Warning Colours of 

 caterpillars is due in the first instance to Darwin, 

 who, reflecting on Sexual Selection, was puzzled 

 by the splendid colours of sexually immature 

 organisms. He applied to Wallace, ' who has an 

 innate genius for solving difficulties.'* Darwin's 



» More Letters, i. 12. " 1876, 97. 



' The Naturalist in Nicaragua (2nd edit.), Loudon, 1888, 321. 



* Descent of Man, 325. On this and the following page an 

 excellent account of the discovery will be found, as well aa in 

 Wallace's Natural Selection, 1875, 117-22. 



