292 



A YEAR IX SCIENCE 



young insects are killed. A newer method of fighting- 

 insects is the introduction of one species of insect to 

 attack and to keep in check another species of insect. 

 This method has proved quite successful in the Cali- 

 fornia orange orchards. It was found that a little black 

 and red beetle of Australia fed upon one of the scale 

 insects which was very injurious to orange trees. These 



Fig:. 144. 



Permission of U. 8. Dept. of Agriculture. 

 Australian ladybird beetle and fluted scale ; A, larvae 



of beetle feeding on scale; B, pupa of beetle; C, adult beetle ; D 

 orange twig showing scales and beetles. 



beetles were introduced into scale-infested orange 

 orchards. They increased in numbers, fed upon the 

 scale insects, and in a few years practically relieved the 

 California growers of all anxiety concerning the scale 

 insects. 



Questions 



1. Name the principal domesticated animals. 



2. Learn, if possible, from what wild form each 

 of these has come. 



