Insects and Insectivorous Birds. 23 



f~ I feel quite satisfied from actual experiment^ that this 

 distribution of colour is a great advantage to ihsse 

 diurnal species in the struggle for existence. 



As before reraai'kei, the bird seizes the most conspi- 

 cuous part, which is very fragile ; thus giving the insect 

 another chance of escape, with a small notch only out of 

 the under-wing. I once saw Triphcena fimbria in broad 

 daylight rise to a great height, pursued by a swallow, 

 which made several inefi'ectual attempts to seize it, and 

 it certainly eflfected its escape ; the swallow giving up 

 the pursuit, completely baffled. 



I have also seen a moth, Macaria notata, fly very fairly 

 with only the two fore-wings developed, not, perhaps, 

 quick enough to avoid such a swift bird as the swallow, 

 but sufficiently to enable this wood-haunting species to 

 reach a thicket in safety. 



The sudden manner in which the brilliantly coloured 

 under- wings are displayed, is another great advantage to 

 the insect ; the bird is startled, and draws back ; and 

 before it recovers its surprise, the prey escapes. 



The flight of the TripJicence, and their mode of unex- 

 pectedly rising from, and quickly dropping into, the 

 herbage, and concealing themselves, is exactly the same 

 as that of some species of European grasshoppers belong- 

 ing to the genus CEdipoda, which also display bright 

 crimson or blue under-wings, combined with earthy 

 coloured upper-wings ; and I have no doubt are benefited 

 in the same manner by a similar distribution of colours. 



The results obtained with the larv£B and pupge of Lepi- 

 doptera were of a more decisive and satisfactory character. 



I found that all hairy caterpillars were uniformly 

 uneaten. The species experimented with were Arctia 

 caja, Eriogaster lanestris, Porthesia auriflua, and Orgyia 

 antiqua ; none of these species were even examined by 

 the birds, and were permitted to crawl about the aviary 

 for days with impunity. 



I am disposed to consider that the flavour of all these 

 larvee is nauseous, and not that the mechanical trouble- 

 someness of the hairs prevents their being eaten. 



In order to throw some light on this point, I made an 

 experiment with Spilosoma menthastri ; this species in 

 the larval state is always rejected, but being fortunate 



