252 INVERTEBRATE ZOOLOGY 



wrought by other insects. Likewise, the Hymenoptera and the 

 Diptera include many useful species in that they are frequently 

 parasitic upon and cause the death of destructive insects. The 

 illustrations cited here are only a start in the enumeration of the 

 economically significant representatives of the class Insecta. 



Outline of Classification 



Phylum Arthropoda, concluded. 



XI. Class Insecta. — Three pairs legs; typically two pairs wings; head, 



thorax, and abdomen distinct; air breathers. 

 See table giving The Orders of Insects (page 251). 



References 



(See general references at close of Chapter I) 



COMSTOCK, J. H. 1924. "An Introduction to Entomology." 3d. ed. 

 Ithaca, N. Y., Comstock. 



and Comstock, A. B. 1915. "A Manual of the Study of Insects." 



Ithaca, N. Y., Comstock. 



EssiG, E. O. 1929. "Insects of Western North America." New York, 

 Macmillan. 



FoLSOM, J. W. 1922. "Entomology with Special Reference to Its Ecologi- 

 cal Aspects. 3d ed. Philadelphia, Blakiston. 



Herms, W. B. 1915. "Medical and Veterinary Entomology." New 

 York, Macmillan. 



Herrick, G. W. 1914. "Insects Injurious to the Household and Annoy- 

 ing to Man." New York, Macmillan. 



Kellogg, V. L. 1908. "American Insects." New York, Holt. 



LuTZ, F. E. 1921. "Field Book of Insects." New York, Putnam. 



MacGillivray, a. D. 1923. "External Insect-anatomy." Urbana, 111., 

 Scarab Co. 



Metcalf, C. L. and Flint, W. P. 1928. "Destructive and Useful 

 Insects, Their Habits and Control." New York, McGraw-Hill. 



Needham, J. G. and Lloyd, J. F. 1930. "The Life of Inland Waters." 

 Springfield, 111., Thomas. 



Sanderson, E. D. and Peairs, L. M. 1920. "Insect Pests of Farm, 

 Garden, and Orchard." New York, Wiley. 



Snodgrass, R. E. 1910. Anatomy of the Honeybee. U. S. Dept. Agr., 

 Bur. Entomol., Tech. Scr:, 18. 



Wheeler, W. M. 1893. A Contribution to Insect Embryology. Jour. 

 MorphoL, 8: 1-160. 



