BENEFICIAL INSECTS 



is formed than when the pollen of a flower fertilizes the ovules 

 of the same flower (self-pollination). Many plants are cross- 



FIG. 44. A, fig insect whose introduction has made Smyrna fig culture possible 



in California. (After Westwood.) 



B, plum blossom ; o, ovary ; p, petal ; se, sepal ; sta, stamen ; st, stigma ; 



s, style. (After Bailey.) 



pollinated only by insects and would not produce good seed if 

 insects did not fly from one flower to another and thus distribute 

 the pollen grains that 

 become attached to 

 their bodies. In some 

 cases the insects seem 

 to realize what they 

 are doing, since they 

 deliberately transfer 

 pollen from the sta- 

 men to the pistil. The 

 plants are benefited 

 directly by the pro- 

 duction of better seed, 



FIG. 45. Predaceous insects. 



and man indirectly A t j ger beet [ e . B European ground beetle im- 



ported to prey upon the gypsy and brown-tail 

 (After Bruner and Howard.) 



moths. 



with larger and better 



crops. In return, the 



insects take nectar from the flowers as their transportation 



charges. 



The dependence of plants upon insects is well illustrated by 

 the Smyrna fig. Prior to the year 1900 this fig could not be 



