446 Mr. C. Schaposclmikow on tlie Red Colour 



and answered in the way that I attempt to set forth in its 

 main outlines in the following pages. My more especial 

 aim in publishing this little paper, however, is that other 

 observers may be thereby induced to give utterance to further 

 remarks and views as to the question under discussion. 



All attempts at explaining the significance of the red colora- 

 tion in the hind wing of Catocala, as recorded in literature, 

 amount to two modes of regarding it, since the red is put 

 down either as a " warning " or as what may be termed an 

 " attractive''^ colour. The latter designation implies that, as 

 interpreted by the authors who hold this view, the signifi- 

 cance of the red colour consists in attracting the bird which 

 is pursuing the moth. According to this theory the bird 

 seizes only the icing, and not the bodi/, of the fugitive insect ; 

 the portion seized tears away, and thus the victim escapes. 

 Explanations such as this have been given by Wallace, 

 Darwin, Poulton, von Bock, Bedar, and others. 



The first-mentioned attempt at explaining the red colora- 

 tion in Catocala as a " warning" colour is, however, opposed 

 by important facts, the first of which is that Catocala, on the 

 approach of an enemy, suddenly departs from its resting- 

 place when that enemy is still at a considerable distance. 

 Secondly, it is only during its most rapid flight that the 

 insect displays the bright colour. These facts can scarcely 

 be used in support of such an interpretation of the colour as 

 that it serves to frighten away the enemy, or else to indicate 

 to it at once that the insect is unfit to eat. Experiments, 

 moreover, lead to the conviction that the pursuing bird seizes 

 the Catocala in its flight by the brightly coloured wing. 



The second attempt at explanation, according to which 

 the red in Catocala is to be regarded as an " attractive " 

 colour, is chiefly based upon observations upon species of 

 Agrotis with yellow hind wings, whence it has been trans- 

 ferred to the species of Catocala with yellow and also to 

 those with red hind wings. With reference to the observa- 

 tions upon Agrotis it must not, however, be overlooked that 

 they were only made in the artificial conditions of an aviary. 

 Moreover, the external resemblance between Agrotis and 

 Catocala in no way justifies us in attributing to their similar 

 coloration the same biological significance in the struggle for 

 existence, and still less are we entitled to do so seeing that 

 there is to start with a very considerable difference in the 

 mode of life of the two genera. Besides this, it is still 

 doubtful whether the principle in question can even be 

 applied to all species of Agrotis with yellow hind wings ; 

 there is a series of transitional forms, ranging from the large 



