248 NATURE STUDIES. 



the tree by driving away their leaf-eating relations. 

 In almost every case, one may say that where sugar 

 is found in any organ of a plant, it is placed there for 

 the sake of engaging the attention of some animal 

 ally; while, conversely, all flower-feeding and fruit- 

 eating creatures always manifest a marked taste for 

 sweet substances, dependent upon their long habitua- 

 tion to sugary food. 



Not only, however, are the grapes sweet, but they 

 are also brightly coloured. Naturally, among succu- 

 lent fruits bidding for the attention of birds, those 

 would best succeed which were most visible at some 

 little distance. Accordingly, just as the insect- 

 fertilised flowers have developed brilliant pigments in 

 their petals, so the fruits which depend upon birds for 

 the dispersion of their seeds have acquired prettily- 

 coloured coverings. We all know how noticeable are 

 the hips and haws, the holly-berries and rowan- 

 berries, even among our northern woodlands ; while 

 the oranges, mangoes, and pomegranates of the 

 tropics appeal ev-en more vividly to the sharp eyes of 

 monkeys, parrots, and toucans. At the same time, 

 it is noteworthy that the tastes of birds with regard 

 to colour seem to differ somewhat from those of 

 insects ; for, as Mr. Wallace points out, white, 

 which is a common colour for flowers, is rare 

 among fruits; while purple and bluish-black, which 

 are seldom met with among flowers, may almost be 

 considered as the ordinary colours of most wild 

 fruits. 



