about something. Look closely and you will see it apparently sting 

 the plant louse. You will find that there are a great number of these 

 little flies, and all hard at work. What are they doing? They are 

 laying their eggs inside of the bodies of the plant lice and when these 

 eggs hatch the young flies will feed upon the lice and soon eat them 

 up. If you will look again in a week or ten days you will probably 

 find that the lice have all disappeared and the oat crop has been 

 saved. 



One more familiar example. Go into the garden in August and 

 September and examine the tomato worms. Some of the worms will 

 be almost completely covered with little white objects that look like 

 Uttle eggs. Look at them more closely through your magnifying 

 glass and you will see that they are little cocoons. 'Where did they 

 come from? This worm has had a great many little eggs laid within 

 its body; they have hatched and the young, having fed upon the 

 worm imtil they were full grown, have come out and spun little 

 silken cocoons upon the outside in order that the full-grown flies 

 may get out easily when the proper time comes. The worm, which 

 is very destructive to the tender plant, will soon die. 



There is still one family of flies of which I wish to speak l(j you. 

 The flies are very small, in fact, among the smallest of all known 

 insects, but there are so many of them that the family is a ver>- large 

 one. As you will not be able to see them, I will tell you how they 

 work. The female fly bores a tiny hole through the sliell of the eg.c; 

 of some other insect and lays her egg inside of the other. When it 

 hatches the young fly or larvas feeds upon the other egg until it is 

 full grown. In this way great numbers of injurious insects are 

 destroyed while yet in the egg. 



I think now you will understand why these little insects of which 

 we have been speaking should be classed among our insect friends. 



