240 PRODUCTIVE FARMING 



There are certain parasitic insects living on the more 

 injurious forms and this aids materially in the control of 

 insect pests. (See Figs. 140, 141.) 



EXERCISE. Parasites of Insects. In the breeding cages 

 or in the boxes where cocoons are kept, watch carefully for 

 the indications of parasites. Some of them may be similar 

 to one or more figures in this chapter. 



Toads as Insect Destroyers. The common toad, found 

 in the garden, lives almost entirely upon insects. He eats 

 enormous numbers, most of which are of the harmful kinds. 



FIG. 139. 15-spotted lady-beetle: a, larva; 6, pupa; d-g, adult varieties. (From 

 Smith's "Insect Friends and Enemies.") 



Toads have no harmful habits. They should be protected 

 because of the good they do. A single full-grown toad will 

 do several dollars* worth of good in a garden each season. 



BIRDS AND THEIR VALUE TO AGRICULTURE. 



Birds are one of the most effective means of retaining the 

 so-called " balance hi Nature." That is, it may be seen that 

 in certain seasons, or hi places where insects are unusually 

 destructive, more birds than usual will be found, busily eat- 

 ing up the insects. Or if the weed crop is very abundant the 



