448 Mr. C. Scliaposchnikow o)i the Red Colour 



liind wings, we almost always find a more or less broad 

 black margin. The pursuing bird will accordingly always 

 endeavour to seize the ])ortion of the wing that lies nearer to 

 the body, /. e. the basal half; but if it does so it is doubtful 

 whether the victim can tear itself free. 



Let us now refer to a hypothesis — purely an abstract one, 

 indeed — which is indispensable if we would explain the bright 

 coloration as attractive. We actually find in nature a series 

 of examples showing that in self-defence an animal sacrifices 

 the portion of its body by which its enemy seizes it ; thus, 

 for instance, the lizard abandons its tail and certain spiders 

 sacrifice their long legs. In all such cases the part of the 

 bod}^ that is shed is regenerated. In the case of moths an 

 analogous reproduction naturally cannot take place, and with 

 them therefore a safeguard of this kind must continue to be 

 accidental and only possible on one single occasion. 



If, however, in spite of all these considerations, we would 

 still apply the above-mentioned principle to Catocala also, we 

 shall have to meet the question as to how it is affected by 

 natural selection. 



When motionless, and so long as it remains upon a parti- 

 cular spot, the moth is unable to make use of the " attractive " 

 coloration ; for this purpose it must be in motion and on the 

 wing. If, however, during its flight it abandons a portion of 

 its wings to the pursuing bird, it will scarcely satisfy the 

 latter by so doing, and can consequently not free itself from 

 further pursuit. The sacrifice of a part of its wings at most 

 enables the moth to gain a little time, while, on the contrary, 

 the lizard, for instance, which sacrifices part of its tail, utilizes 

 the few moments so gained to disappear into a hole or cleft 

 in a rock. The moth with " attractive " coloration would be 

 compelled to fly on and to make use of a suitable moment in 

 order to conceal itself. It follows that in its case there would 

 have to be developed, firstly, a quick and adroit flight, and, 

 secondly, the capacity of concealing itself unnoticed. The 

 struggle for existence was bound first of all to evolve so much 

 the more strength and adroitness of flight, since with the 

 loss of or injury to the hind wing exhibiting the attractive 

 coloration its attractive role as such disappears. It follows 

 that only those individuals would survive that by dint of 

 concealing themselves unnoticed were able to turn their flight 

 to the best account and escape the sacrifice of a portion of 

 their wings, i. e. those that made least use of the " attractive " 

 coloration in order to " attract,-''' The ultimate object of the 

 flight would be to settle unobserved by the enemy and to 

 obtain concealment by means of the mimetic coloration of the 



