[23] Cf. supra, p. [18].

[24] “The Play of Animals,” translated by Elizabeth L. Baldwin, p. 62.

[25] George W. and Elizabeth G. Peckham, “On the Instincts and Habits of the Solitary Wasps,” p. 231.

[26] “Lectures on Human and Animal Psychology,” pp. 388, 397, 399.

[27] “Instinct and Reason,” pp. 90, 92.

[28] “Instinct and Reason,” p. 91.

[29] Chapter I., Section [V].

[30] “On the Habits and Instincts of the Solitary Wasps,” by George W. and Elizabeth G. Peckham (1898).

[31] “Mental Evolution in Animals,” p. 299.

[32] “Organic Evolution,” translated by J. T. Cunningham, p. 280.