110 LIFE ON THE FARM. 



weak and abnormal. Weakness and deformity are 

 transmitted from generation to generation, till the 

 plant is no longer able to cope with others in the 

 struggle of life and thus dies and gives place to 

 stronger forms. 



CROSS-FERTILIZATION BY INSECTS. 



Nature is very careful to secure cross-fertiliza- 

 tion in plants. The visits of insects to the blos- 

 soms to secure the nectar that they find there is 

 the greatest means by which cross-fertilization is 

 accomplished. To secure the carrying of pollen, 

 plants have to pay for it by expending extra 

 strength in producing pleasant odors, sweet nectar, 

 bright-colored blossoms, and such attractive things. 

 Insects would not carry pollen from one blossom to 

 another were there not some reward for their doing 

 it. Odor and color are probably guides to the 

 sweets held by the blossoms. In securing nectar 

 from the blossom, the insect unconsciously rakes off 

 some pollen on his legs and body, and carries it to 

 another blossom, thus accomplishing the desired 

 result. 



It must be remembered, however, that the pollen 

 of one blossom will do no good upon the blossom 

 of a different kind of plant. For instance, the pol- 

 len from an apple blossom carried by a bee to a 

 pea blossom would not produce apples on the pea 

 vine. Nature, again, has so ordered it that insects 

 visit only one kind of plant while it blossoms, and 



