202 BIOLOGY FOR BEGINNERS 



p. 234; Textbook of Zoology, Linville and Kelly, pp. 11-14; Elemen- 

 tary Zoology, Kellogg, pp. 161-163; Injurious Insects, Treat, p. 269; 

 Injurious Insects, Saunders, p. 157; Introduction to Zoology, Daven- 

 port, pp. 1-4; Economic Zoology, Smith, pp. 11-51, 79-100; Economic 

 Zoology, Kellogg and Doane, pp. 14-25; Descriptive Zoology, Colton, Chap. 

 I-III; Practical Zoology, Davison, Chap. I-VII; Farm Bulletins, Nos. 

 47, 59, 70, 80, 132, 209, 211, 247, 264, 284. 



SUMMARY 

 Characteristics of Insects: 



Separate head, thorax, and abdomen. 

 One pair antennae, three pair legs. 

 Usually two pair wings. 

 Breathe by means of tracheae. 



High degree of specialization (adaptation) because of 

 Severe struggle for existence, because of 



Very large number of species and individuals. 



Specialized for various foods: 



Vegetable foods Grasshopper (biting) 



Blood suckers Mosquitoes 



Sap suckers Bugs and scale insects 



Scavengers Flies and beetles 



Nectar Bees and moths 



Specialized for locomotion: 



Crawling Beetles, etc. 



Flying Bees, etc. 



Jumping Grasshopper 



Swimming Beetles and some bugs 



Water surface Striders 



Burrowing Ants, etc. 



Specialized instincts: 



(See references on Bees, Ants, Wasps, Termites). 

 General Structure: 



1. Exo-skeleton, chitin, light, strong, and protective colored. 



2. Regions: 



Head for sense and food-getting organs. 

 Thorax for locomotion (respiration). 

 Abdomen for reproduction and breathing (ear). 

 Head: 



Antennae, one pair, functions, cf. crayfish. 

 Eyes, simple, three, location, 

 compound, structure, why not on stalks? 



