PKOTECTIVE AND AGGRESSIVE MIMICRY 261 



I offered a mature larva of the same kind to a 

 full-sized Green Lizard (Lacerta viridis), and closely 

 watched the encounter. The lizard was evidently 

 suspicious, and yet afraid to attack the caterpillar, 

 which maintained the terrifying attitude in the most 

 complete manner throughout. The lizard kept boldly 

 advancing and then retreating in fright ; but at each 

 advance it approached rather nearer to the caterpillar. 

 After this had taken place many times and nothing 

 had happened, the lizard grew bolder and ventured 

 to gently bite what appeared to be the head of the 

 caterpillar ; it then swiftly retired, but finding that 

 there was no retaliation, it again advanced and gave 

 a rather harder bite. After a few bites had been given 

 in this cautious manner, the lizard appeared satisfied 

 that the whole thing was a fraud, and devoured the 

 caterpillar in the ordinary manner. There could be 

 no doubt whatever that the lizard was intimidated at 

 first, and that its alarm was due to the appearance of 

 the caterpillar. I had often given the same lizard 

 equally large hawk moth caterpillars of other species, 

 and they were invariably attacked and devoured with- 

 out any ceremony. I have never seen a lizard behave 

 with such caution as on the occasion I have just 

 described. 



Lizards have good reason for such an instinctive 

 dread, for the appearance suggests that of one of their 

 most terrible foes. Mr. Belt graphically describes the 

 pursuit of a lizard by a snake. 'I was once standing 



