200 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 



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ordinary workers (sterile females of the first type), soldiers (sterile 

 females of the second type), and sometimes officers (especially large 

 and powerful sterile females that seem to direct the line of march in 

 legionary ants). All of these casts are produced from the eggs of one 

 female and are the result of various special diets permitted the larvae 

 by the workers. Among bees, similarly, there is one queen, a number 

 of drones (males), and the sterile female workers, who perform the 

 functions of nursing the larvae, cleaning up the hive, collecting pollen 

 and nectar, and making honey and wax. Detailed accounts of the 

 lives of bees have been given by various authors, notably by Maeter- 

 linck in his Life of the Bee. 



COLOR IN ANIMALS 



''The phenomena of color in both animals and plants," says 

 Metcalf,^ "are among the most remarkable and interesting in the 

 whole realm of nature. It is not so much the way in which the color 

 is produced, whether by pigments or by refraction, that interests us 

 in this connection, as it is the uses to which colors are put. Let us 

 first refer to the colors of animals. 



"According to the uses to which colors in animals are put, we 

 may classify them, for purposes of description, as follows: 



"Indifferent coloration, not useful, so far as we can judge; 



Colors of direct physiological value; 



Protective coloration and resemblances; 



Aggressive coloration and resemblances; 



Alluring coloration and resemblances; 



Warning coloration; 



Immunity coloration; 



Mimetic coloration and resemblances; 



A. Protective 



B. Aggressive 



Signals and recognition marks; 

 Confusing coloration; 

 Sexual coloration." 



A few examples of these categories of animal coloration will serve 

 to illustrate the ways in which they are believed to be adaptive and 

 thus better to fit the organism for its struggle for existence. 



Protective resemblance. — Many animals that live at or near the 

 surface of the sea are practically transparent. Fishes are commonly 



^ M. M. Metcalf, Organic Evolution (191 1). 



