WARNING COLOURS AND MIMICRY 147 



the upper surface may exhibit attractive tints. Again, 

 warningly coloured butterflies are leisurely in their flight. 

 They flutter in an unconcerned manner along the forest 

 glades, or from flower to flower, as though experience had 

 freed them from that instinctive dread of hostile attack 

 which is common to most animals. Nor is this confidence 

 misplaced. When in Nicaragua, the naturalist Belt be- 

 came convinced that birds, dragon-flies, and lizards avoid 

 the Heliconine butterflies, because their wings were not 

 found lying about in places where insectivorous creatures 

 were accustomed to feed ; whereas wrings of the edible 

 forms were so found. He also relates that a pet white-faced 

 monkey always refused to eat Heliconine butterflies when 

 these were offered to it. Similar facts have been recorded 

 by competent observers anent the protected butterflies of 

 Africa and the Indian region. 



Clearly the weight of evidence goes to prove the 

 usefulness of warning colours to those insects which 

 display them. Yet we cannot claim that conspicuous 

 colours imply complete immunity from molestation. It 

 has already been shown that many protected insects must 

 necessarily fall victims to inexperienced assailants. But 

 apart from this, observers have generally found that a 

 warningly coloured insect which is avoided by some, per- 

 haps by most, insectivorous animals, is readily eaten by 

 one or a few kinds. It has also been proved by experi- 

 ment that a hungry animal will often eat an insect which 

 would otherwise be refused. Again, certain kinds of 

 birds, such as cuckoos, feed largely and by preference upon 

 hairy and spiny caterpillars. It is clear, therefore, that 

 noxious qualities and their associated colour signals are 

 of little or no protection against some enemies ; nor is 

 this a matter for wonder. " No kind of protection," says 

 Professor Carpenter, "can avail at all times and in all 



