140 THE NATURE STUDY COURSE. 



squash-bug and plant-lice, have their jaws modified, to form 

 sucking-tubes. Knowledge of mouth structure is necessary in 

 studying methods of combating injurious insects. 



Relations to man : — Beauty of color and motion ; honey ; 

 silk ; scavenging ; pollinating flowers ; destroyers of other 

 injurious insects ; food for poultry j destruction of fruit-trees, 

 garden and farm crops, forests ; conveyors of disease ; injuries 

 to large animals and annoyance to man. 



Relations to flowers as pollen carriers. 



Relations to animals, as food of birds, bats, fishes, toads and 

 snakes. 



Predaceous and parasitic species : — The larvae, and to some 

 extent, the adults of lady-bugs, lace-wings, syrphus and 

 dragon-flies prey upon their fellows; ichneumon flies deposit 

 their eggs in the larvae of other insects ; ant-lions and spiders 

 make traps to catch insects. 



Study the relations of injurious insects to the plants 

 upon which they feed, as the potato-beetle, the squash-bug, 

 cabbage-butterfly, tomato-worm, grape-sphinx, etc. Observe 

 the different kinds of insects that feed upon particular plants, 

 as the rose, the apple, the maple. 



Books from which assistance may be obtained : — " Guide to 

 Nature Study," pp. 274-308 ; " Public School Nature Study," 

 pp. GO-81, 108; Silcox and Stevenson's "Modern Nature 

 Study," pp. 129-187 ; S. J. Hunter's "Elementary Studies in 

 Insect Life"; C. M. Weed's "Nature Biographies"; W. H. 

 Gibson's "Blossom Hosts and Insect Guests"; and Comstock's 

 "Insect Life." Mary C. Dickerson's "Moths and Butterflies," 

 with 200 photographs, is a Nature Study treatment of these 

 two groups. 



