408 ECONOMIC INSECTS 



8. Life-histories of insects should be studied wherever possible, and all 

 points observed should be noted and reported. 



9. Insects Destroyed by Birds. Make observations regarding the destruc- 

 tion of insects by various birds and estimate the number of insects destroyed 

 in a given time by birds, particularly during their nesting season. 



10. Toads in Gardens. Make similar studies regarding the value of toads. 



11. Cocoons and their Parasites. Collect many specimens of any kind 

 of cocoon, such as the tent caterpillar. After collecting 100 or more, allow 

 them to develop for a few weeks, and then dissect them all, and decide what 

 proportion are healthy and normal, and what proportion have already been 

 destroyed by parasites. The great. value of parasitic insects may thus be 

 appreciated. 



12. Amount of Insect Work. Interesting studies of the destructive work 

 of any of the biting insects may be made. Study the amount of destruction 

 wrought by the corn ear-worm, the potato beetle, the tomato worm, the 

 codling moth or any of the others common in the vicinity. 



13. Detect Insects by their Work. Learn to recognize the minute in- 

 sects, such as San Jose scale, plant lice and others. Not only the structure 

 and appearance of the insects, but also the appearance of the plants when 

 attacked should be recognized. 



14. Tree Borers. Examine orchard trees for borers and practice destroy- 

 ing them with a knife or wire. 



QUESTIONS 



1. Classify true insects according to mouth parts. 



2. What is the difference between complete and incomplete metamorphosis 



in insects? 



3. Mention the chief orders of insects with examples of each. 



4. What natural enemies of insects aid in their control? 



5. Give some idea of the value of these. 



6. Mention three garden insects which are injurious in your section, and state 



to what order they belong, and what kind of mouth parts they have. 



7. Make another group of fruit insects. 



8. Tell what you can of the San Jose scale. 



References. United States Farmers' Bulletins: 99, Insect Enemies of 

 Shade Trees; 172, Scale Insects and Mites on Citrus Trees; 264, The Brown- 

 tail Moth and How to Control It ; 275, The Gipsey Moth and How to Control 

 It; 453, Danger of Spread of Gipsey and Brown- tail Moths Through Imported 

 Nursery Stock; 543, Common White Grubs; 557, The Potato Tuber Moth; 

 606, Collection and Preservation of Insects and other Material for Use in the 

 Study of Agriculture; 626, The Carpet Beetle, or "Buffalo Moth;" 627, The 

 House Centipede; 636, Chalsis-fly in Alfalfa Seed; 637, Grasshopper Problem 

 and Alfalfa Culture; 640, Hessian Fly; 657, Chinch Bug; 658, Cockroaches; 

 659, True Clothes Moth; 662, Apple Tree Tent Caterpillar; 675, Round- 

 headed Apple Tree Borer; 679, House Flies; 681, Silver Fish: An Injurious 

 Household Insect; 683, Fleas as a Pest of Man and Animals; 691, Grass- 

 hoppers on Sugar Beets and Truck Crops; 701, Bag Worm: An Injurious 

 Shade Tree Insect; 705, Catalpa Sphinx; 708, Leopard Moth: An Enemy of 

 Shade Trees; 721, Rose Chafer; 722, Leaf Blister Mite; 723, Oyster-shell 

 Scale and Scurfy Scale; 725, Wireworms Destructive to Cereal and Forage 

 Crops; 731, True Army Worm and Its Control; 737, Clover Leafhopper; 739, 

 Cutworms and their Control; 740, House Ants; 741, The Alfalfa Weevil. 

 Also: Nos/223, 284, 290, 456, 493, 506, 564, 609, 621, 630, 733, 735. 



Economic Entomology, Smith, J. B. Lippincott Co., Phila. 



