Insect Enemies and Allies 



191 



W. T. Stilling 



FIG. 143. For the study of insects as they live on a plant, a cage can readily 

 be made of a covered lamp chimney or the top of a flytrap. 



bugs, army worms, and grasshoppers is well known. 

 On the other hand, it was found impossible to raise red 

 clover in Australia, where it had been introduced from 

 England, until the bumblebee, the clover's friend, was 

 brought also. Smyrna fig trees never ripened a single 

 specimen of their fruit in California until, after years 

 of failure, a little insect was imported from Smyrna 

 and turned loose in the orchards to carry pollen from 

 tree to tree. 



The life histories of insects. The higher animals are Metamor- 

 of much the same form from birth to old age, but insects p OSIS 

 pass through several changes during their lifetime (Figs. 



