IN DEFENSIVE COLORATION 317 



esting notes on the subject. 1 Fritz Miiller has also shown 

 in S. America that the scents of male butterflies are 

 agreeable.- Far stronger evidence is of course afforded 

 by offering forms with Warning Colours to their natural 

 enemies, and stronger still by watching the behaviour of 

 enemies in the wild state and by keeping a precise record 

 of the food found in their stomachs. Although an im- 

 mense amount of such evidence is still required, a great 

 deal has been done. The summary of Mr. Frank Finn's 

 striking experiments in India has been quoted on p. 269. 3 



2. Species with Warning Colours depend for their Exis- 

 tence tipon the Co-Existence of Palatable Species. — Apose- 

 matic Colours, together with the qualities they indicate, 

 depend for their very existence upon the relative abun- 

 dance of palatable food supplied by animals with Cryptic 

 Colouring. Unpalatability or even the possession of a 

 sting is not sufficient defence unless there is enough food 

 of another kind to be obtained at the same place and time. 4 

 Hence insects with Warning Colours are not seen in 

 temperate countries except during the months when insect 

 life as a whole is most abundant ; and in warmer countries, 

 with well-marked wet and dry seasons, it is found that 

 Warning Colours are less developed in the latter season, 

 which is the time of greater stress. Examples will be 

 given in later Sections. 



3- Erroneous Assumption that Warning Colours imply 

 Complete Immunity from Attack. — Although animals 

 with Warning Colours are probably but little attacked 

 by educated enemies of their class, they have special 

 foes which keep the numbers down. Thus the 

 cuckoo appears to be an insectivorous bird which will 

 freely devour conspicuously coloured larvae unpalatable 



1 Proc. Ent. Soc, Lond., 1904, p. Ivi; 1905, pp. xxxvii, liv; 1906, p. ii. 

 See also G. B. Longstaft' in Proc. Ent. Soc, Lond., 1905, p. xxxv, and 

 Trans. Ent. Soc, Lond., 1905, p. 136. 



2 Jen. Zeit., vol. xi, p. 99 ; Trans. Ent. Soc, Lond., 1878, p. 211. 



3 See also Proc Zool. Soc, Lond., 1887, p. 191, for an account of all 

 the work done up to that date, and Trans. Ent. Soc, Lond., 1902, p. 287, 

 for the most important of recent researches on the subject. 



4 Proc Zool. Soc, Lond., 1887, p. 191 ; confirmed also by F. Finn : 

 see p. 269 of the present volume. 



