1 20 On Flowers and Insects. 



II. 



1. Everyone knows how important flowers are to 

 insects ; every one knows that bees, butterflies, &c., 

 derive the main part of their nourishment from the 

 honey or pollen of flowers, bnt comparatively few 

 are aware, on the other hand, how much the flowers 

 themselves are dependent on insects. Yet it has, 

 I think, been clearly shown that if insects have 

 been in some respects modified and adapted with a 

 view to the acquirement of honey and pollen, 

 flowers, on the other hand, owe their scent and 

 honey, their form and colour, to the agency of 

 insects. Thus the lines and bands by which so 

 many flowers are ornamented have reference to the 

 position of the honey ; and it may be observed that 

 these honey-guides are absent in flowers which open 

 at night, where they of course would not show, 

 and would therefore be useless. Flowers, more- 

 over, which are generally pale for instance, the 

 White Lychnis open in the evening ; while those 

 of a deeper hue, such as the Red Lychnis, flower 

 by day. 



2. Indeed, it may be laid down as a general rule, 

 that those flowers which are not fertilised by honey- 

 seeking insects as, for instance, those of the Dock 

 (fig. 27), the Beech, and most other forest trees 



