224 We Barton's 



count of their long, contracted nectaries, have 

 become, as we have seen, gradually developed 

 or modified through the agency of their visitors ; 

 while the colors, odors, and periods of opening 

 of flowers generally are in relation to the tastes 

 and habits of the insects that frequent them. 

 Odor, no less than conspicuousness, is a power- 

 ful magnet to the insect tribes ; indeed, strong 

 scent is even a greater attraction than brilliant 

 colors. 



Many flowers are both conspicuous and odor- 

 iferous. On this point Darwin observes : " Of 

 all colors, white is the prevailing one ; and of 

 white flowers a considerably larger proportion 

 smell sweetly than of any other color, namely, 

 14.6 per cent ; of red, only 8.2 per cent are odor- 

 iferous. The fact of a large proportion of white 

 flowers smelling sweetly may depend in part on 

 those which are fertilized by moths requiring the 

 double aid of conspicuousness in the dusk and 

 of odor. So great is the economy of Nature, 

 that most flowers which are fertilized by crepus- 

 cular or nocturnal insects emit their odor chiefly 

 or exclusively in the evening. Some flowers, 

 however, which are highly odoriferous depend 

 solely on this quality for their fertilization, such 

 as the night- flowering stock (Hesperts] and 

 some species of Daphne ; and these present the 



