712 tup: butteiifltes of new England. 



field observations showed him that the mimicking species belonged to a 

 o-ronp very subject to attack by birds and other foes, while the group of 

 butterflies which they mimicked had an offensive odor and apparently a 

 taste obnoxious to insectivorous animals, so as to be practically exempt 

 from their attacks. This was partly shown by their exceptional abun- 

 dance, whicli did not seem to accord with slow and easy flight and con- 

 spicuous coloring, features that would naturally render them an easy prey 

 to their enemies. That these butterflies were truly distasteful to birds has 

 been shown over and over again. Thus Belt says : — 



"I had an opportunity of proving in Brazil that some birds, if not all, 

 reject the Heliconii butterflies, which are closely resembled by butterflies 

 of other families and by moths. I observed a pair of birds that were 

 brino-ing butterflies and dragonflies to their young, and although the Heli- 

 conii swarmed in the neighborhood and are of weak flight so as to be 

 easily caught, the birds never brought one to their nest. I had a still 

 better means of testing both these and other insects that are mimicked in 

 Nicarao'ua. The tame, white-faced monkey I have already mentioned 

 was extremelv fond of insects, and would greedily munch up any beetle or 

 butterfly given to him, and I used to bring him any insects that I found 

 imitated by others to see whether they were distasteful or not. I found 

 he would never eat the Heliconii. He was too polite not to take them 

 when they were offered to him, and would sometimes smell them, but in- 

 variably rolled them up in his hand and dropped them quietly again after 

 a few minutes. A large species of spider (Nephila) also used to drop 

 them out of its web when I put them into it. Another spider that fre- 

 quented flowers seemed to be fond of them and I have already mentioned 

 a wasp that caught them to store its nest with. There could be no doubt, 

 however, from the monkey's actions, that they were distasteful to him." 

 (Naturalist in Nicaragua, 31G-317.) 



Bates very naturally argued that if these offensive properties gave the 

 Ithomyiae such exemption from attack as enabled them to swarm in spite 

 of lazy habits and brilliant coloring, then other butterflies living in the 

 same places would gain a certain amount of freedom from attack, if their 

 flight and coloring so nearly resembled those of the offensive species as 

 actually to deceive insect-eating animals, even though they were themselves 

 in no way distasteful. 



The fact of a resemblance so close that it is to all appearances a "pal- 

 pably intentional likeness" is impossible to question. But how explain it? 

 How could a butterfly change its appearance to such a degree, its wings 

 from a uniform color to a banded, streaked and spotted pattern and at the 

 same time lengthen tlaeir form, and extend the antennae? "Can the Ethi- 

 opian change his skin or the leopard his spots ?" 



Tlie answer, as Bates clearly saw, was to be looked for in the same 



