126 ANIMAL ECOLOGY 



An excellent example of the character of the competi- 

 tion with which an animal meets when extending 

 its range into new territory. See diagram, p. 44. 



WHEELER, W. M. 



1906. An Ethological Study of Certain Maladjustments in 



the Relations of Ants to Plants. Bull. Amer. Mus. 

 Nat. Hist., Vol. XXII, pp. 403-418. 

 Competition between plants and ants. 

 MASSART, J., and VANDERVELDE, E. (Trans. W. MACDONALD.) 



1907. Parasitism Organic and Social. Second Edition. Re- 



vised by J. Arthur Thompson, pp. 124. London. 

 Contains many examples of responses to a parasitic 

 environment. 



Selected References on the Struggle for Existence 

 (Alphabetically arranged) 



BEAL, F. E. L. 



1911. Food of the Woodpeckers of the United States. U. S. 

 Dept. Agr., Bur. Biol. Surv., Bull. 37. pp. 64. 



CHAPMAN, F. M. 



1902. The Economic Value of Birds to the State. Seventh 



Rep. N. Y. Forest, Fish, and Game Comm., 1901, 

 pp. 115-176. Reprint, pp. 66, 1903. Albany. 

 Contains an extensive list of papers on the food of birds. 



EICHELBATJM, E. 



1910. Uber Nahrung und Ernahrungsorgane von Echinoder- 

 men. Wiss. Meeruntersuch, heraus. von der Komm. 

 zvir wiss. Unter. der deutsch. Meere in Kiel. N. F. 

 Bd. XI, Abth. Kiel, pp. 187-275. 

 FORBES, S. A. 



1883. The Food Relations of Predaceous Beetles. Twelfth 

 Rep. State Ent. 111., pp. 105-120. 



1903. The Food of Birds. Bull. 111. State Lab. Nat. Hist., 



Second Edition, Vol. I, pp. 86-161. 



