220 NATURE STUDY AND AGRICULTURE 



disk or cultivator in order to destroy the smart weeds, and 

 as many of the ants' nests as possible. 



The life history of all other aphids is essentially the 

 same as that of the corn-root louse. One reason they are 

 so destructive is because they multiply so rapidly. 



One species of aphid is often found on the oats in early 

 summer. It is known in some localities as the " green 

 bug." It sucks the juice from the stems and leaves of the 

 oats and is often very destructive. 



Aphids have many natural foes. Among these are the 

 ladybug beetles, the aphis lion, braconid and syrphus flies, 

 as well as a number of birds. 



The White Grub. White grubs may be studied either 

 in autumn or spring. They are found abundantly in the 

 soil of fields and gardens, in potato patches, and often in 

 pastures and lawns where they kill our great areas of grass. 



Ask the pupils to save and bring in some white grubs. 

 To keep these insects alive place them in a tin can or pail 

 in which there is plenty of moist soil. Place on top of the 

 soil a piece of fresh grass sod, firm it down with your hand 

 gently, keep it watered but not made wet. Set the pail 

 aside for several days. At the end of this time carefully 

 lift up the sod. You will probably find some of the grubs 

 under it. Note the position of the body. Is there any 

 advantage in keeping it curled up in this fashion ? Is the 

 grub lying on its back or under side ? Has it a tunnel to 

 lie in ? What has it been doing here ? Look at the grass 

 roots. Can you see whether any of these have been eaten ? 

 Look carefully at the structure of the insect. Has it a 

 distinct head? How does this differ in color from the 

 body? Is the body hard or soft? What kind of a mouth 



