14 CONTROLLED NATURAL SELECTION 



enemy by making some menacing movement ; 

 even quite small animals, insects for instance, 

 will then make threatening motions. Under 

 Eepellent motions would also be classed Warn- 

 ing motions ; those which presuppose know- 

 ledge on the part of the enemy, the attacker ; 

 a knowledge gained by previous association of 

 the motion with some unpleasantness. There 

 is considerable evidence that this kind of 

 motion is frequently mimicked. 



These signals by movement are, as a rule, 

 associated with numerous other displays 

 displays of position, attitude, colour, sound, 

 and scent ; for this reason they are difficult 

 to analyse. It is often difficult to decide 

 whether the motion is the essential or an 

 accessory of the signal. 



(2) Attractive. Motion signals, whose pur- 

 pose is to attract an enemy, although fre- 

 quently overlooked, are also common in 

 Nature. Amongst birds, as mentioned in 

 Chapters V and X under Family Instincts, 

 parents will frequently endeavour, by the 

 making of conspicuous movements, to attract 

 an enemy, to draw its attack. Numerous 

 other examples will be given when considera- 

 tion is made of Sexual Displays. Purposely 

 conspicuous movement is probably, therefore, 



