in the Hind Wing o/Catocala, Schr. 45 L 



and marking into play. In these woods the enemies of the 

 moth, which rests during tlie day upon the trunks of trees, 

 are the birds*, both the scansorial species (Picus, Sitta, and 

 tlieir allies), as also those that pick insects off twigs, or in 

 other cases search for them upon the ground (^Tardus and 

 others of the same group). At night, wlien the moth is on 

 the wing, it is waylaid by bats. From thrush-like birds the 

 red Catocala is sufficiently protected by the height of its 

 resting-place; it scarcely ever settles so near the ground as 

 to attract the attention of birds of this kind, and, again, 

 never at such a heiglit as to fall a victim to birds perching 

 upon twigs. A safe elevation would be at from 1^ to 2| 

 metres from the ground, and it is at about this lieiglit that, 

 as a rule, our red Catocala is actually to be seen. More 

 dangerous to it are the birds that climb and closely search 

 the tree-trunks {Picus, Sitta) ; it is not easy for so large a 

 moth to escape their notice, but all these birds invariably 

 make a noise in climbing, and in our Catocala the sense of 

 hearing appears to be particularly well developed, so that on 

 the approach of woodpeckers and other climbing birds it is 

 always possible for it to flit off from the trunk at the right 

 time. By day it avails itself both of the strength and adroit- 

 ness of its flight, as also of the corresponding wing-coloration, 

 in order by these means to be more or less effectually pro- 

 tected from a bird that may be seeking for it. Though I am 

 acquainted with a considerable number of cases which point 

 to bats as being solely responsible for the destruction of the 

 moth, I am unable to prove a single instance in which a 

 Catocala has been killed by a bird during the day. Nor is it 

 difficult to understand why Catocala is chiefly caught by bats, 

 for bats hunt in the dark and by ear, and against them 

 Catocala can only make a partial use of its distracting flight, 

 while its colour is of no use to it at all. 



What has been stated above as to the enemies of Catocala 

 explains at once the precise kind of region in which existence 

 is possible for a group of moths of fairly considerable size 

 and powerful musculature, the members of which sit upon 

 tree-trunks when at rest and possess mimetic fore wings and 

 brightly coloured hind wings, the coloration of which plays a 

 distracting part in connexion with a distracting flight. For 

 the evolution of a group of moths with the above-mentioned 



* Lizards .and snakes would also come within the category of insect- 

 enemies which climb without noise ; but the tree-lizards tliat inhabit the 

 region in question are too small and not sutticiently numerous, while the 

 tree -climbing snakes are incapable of ascending trunks as thick as those 

 usually chosen by the red Catocala for its resting-place. 



30* 



