SOME COMMON INSECTS 13 



sand grains in again. Can you explain this apparently foolish process ? In 

 the late summer and early fall you will find a great many winged ants com- 

 ing out of the nests. These are mostly males getting ready for the nuptial 

 flight. Find out what the nuptial flight is and the events that happen at 

 this time. 



Aphids. Look for plant lice on the succulent fall weeds, or on the 

 plants in the garden. You will find most of them with their sucking-tubes 

 imbedded in the tissue of the plant from which they are drawing their food. 

 Some of them may be the winged males and females. You will often find 

 ants visiting these colonies of aphids. Watch the ants to see what they 

 do to the aphids. Read Bulletin 131 of the University of Illinois Agri- 

 culture Experiment Station on the "Behaviour and Habits of the Cornfield 

 Ants." Read also W. M. Wheeler's Ants (pp. 267-93 an d 318-36). Look 

 up the facts in regard to the rate of reproduction in the plant lice. 



Wasps. If possible find in th6 woods or around the barn nests of the 

 paper wasps, or under the eaves of the house, barn, or outbuildings the 

 clay nests of the mud-dauber wasps. Watch the wasps to learn as much 

 as possible of their habits. Procure some old nests of either the paper wasps 

 or the mud dauber and examine their method of construction. Can you 

 make out the life-history of the animal ? 



Dragon fly. Watch a dragon fly in its flight. Time it in seconds as it 

 flies from one point to another. Measure the distance and see how many 

 miles an hour it is going. Listen to the hum of a bee and devise a way to 

 tell how many times it flaps its wings in a second. Observe on what the 

 dragon fly feeds. Watch to see how many it eats in the course of a few 

 minutes. What other names has a dragon fly? Are they justified by 

 facts? Watch the dragon fly as it flies over stream or pond. Can you 

 observe it in the act of depositing eggs? The young which hatch from 

 these we shall study later. Draw the wing of the dragon fly. Weigh the 

 wings and the rest of the animal separately. What is the relative weight 

 of wings and body in a modern aeroplane? In what direction do most 

 supporting veins run in the wing of the dragon fly ? In what part of the 

 wing are they? What is the advantage of this? Compare the bracing 

 of the veins in this wing with the system of ribs and braces in an aeroplane 

 wing. 



Insect color. Examine the wing of a butterfly under the low power of 

 the microscope. Rub the wing with the finger and examine the rubbed 

 spot again. What have you on your finger? With what are the wings 

 covered? How are these arranged on the wings? Examine a spot of 

 color. To what is it due? What is the color of the real grasshopper? 

 the katydid? the locust? Where do the two former live? the latter? 



