202 



ENTOMOLOGY 



pollen from one flower to another. In general, the conspicuous colors 

 of flowers are for the purpose of attracting insects, as are also the odors 

 of flowers. Night-blooming flowers are often white or yellow and as a 

 rule strongly scented. Colors and odors, however, are simply indica- 

 tions to insects that edible nectar or pollen is at hand. Such is the usual 

 statement, and it is indeed probable that insects actually do associate 

 color and nectar, even though they will fly to bits of colored paper almost 

 as readily as they will to flowers of the same colors. It is not to be sup- 



FIG. 253. Bumble bee (Bombm} entering flower of blue-flag (Iris versicolor}. Slightly 



reduced. 



posed, however, that insects realize that they confer any benefit upon 

 the plant in the flowers of which they find food. At any rate, most 

 flowers are so constructed that certain insects cannot get the nectar or 

 pollen without carrying some pollen away, and cannot enter the next 

 flower of the same kind without leaving some of this pollen upon the 

 stigma of that flower. Take the iris, for example, which is admirably 

 adapted for pollination by a few bees and flies. 



Iris. In the common blue-flag (Iris versicolor, Fig. 253) each of the 



