hawkins] STUDIES OF AQUATIC INSECTS 95 



compare them in each stage as regards appearance and time re- 

 quired for development. 

 Experiments in Destroying the Mosquito 



Place a counted number of larvae and pupae in a jar with 

 a fish. Observe at periods for day or two. 



In another dish place a tadpole with some larvae. Watch for 

 results. 



Test various kind of water insects. Count the number of 

 larvae used and note how many are eaten in a certain length 

 of time. 



In another tumbler containing larvae, pupae and adults, pour 

 a few drops of kerosene on the surface of the water and note 

 results. 



Which do you consider to be the most important means of 

 destroying the mosquito? Why? What are the most important 

 things to know about their life history in order to destroy them 

 by artificial means? 



Search the neighborhood to find the breeding places of mos- 

 quitoes and see what can be done to lessen the number of these 

 places and to destroy the mosquitoes while breeding. Make a map 

 of the surrounding country showing the location of these breed- 

 ing places. 



Drawings 



Make drawings showing the larva, pupa and adult in their 

 resting positions. 



Literature (for children) 



Bryant's "To a Mosquito" ; Pierson's "Among the Xight 

 Folk", page 15. 

 References (for teacher) 



Comstock's "Insect Life"; Hodge's "Nature- Study and 

 Life". 



The Dragon Fly 

 (Spring) 

 Problem 



Is the dragon fly beneficial or injurious to man? 

 Materials 



Nymph of dragon fly, some receptacle for keeping nymph. 

 Method 



The nymphs may be collected in April and May by means 

 of a water net, or a garden rake by raking up the trash found on 

 the edge of the pool. These should be kept in the schoolroom in 



