232 ENTOMOLOGY 



place the theory of Batesian and Mullerian mimicry upon a 

 substantial foundation of observational and experimental 

 evidence. 



In regard to the important question do birds avoid un- 

 palatable insects instinctively or only as the result of experi- 

 ence the evidence is all one way. Several investigators, in- 

 cluding Lloyd Morgan, have found that newly-hatched birds 

 have no instinctive aversions as regards food, but test every- 

 thing, and (except for some little parental guidance) are 

 obliged to learn for themselves what is good to eat and what 

 is not. This experimental evidence that the discrimination of 

 food by birds is due solely to experience, was evidently highly 

 necessary to place the theory of mimicry especially the Mul- 

 lerian theory upon a sound basis. 



Though butterflies as a group are much subject to the at- 

 tacks of birds in the tropics, there are very few recorded in- 

 stances of this for our temperate region. It may then be 

 asked, what advantage does the "viceroy" (Fig. 243, B) gain 

 by resembling the " monarch," in a region where all butter- 

 flies are exempt from destruction by birds? In reply, it may 

 be said that the premise of the argument is as yet little more 

 than an assumption, because so little attention has been given 

 to the relations between birds and butterflies in our own coun- 

 try. Or, admitting the premise, it may be said that the resem- 

 blance was advantageous once, if not now ; and that in any 

 event, the departure of archippus from its congeners toward 

 one of the Danainse a famous group of " models " in the 

 tropics is unintelligible except as an instance of mimicry. 



Granting that mimicry is upon the whole advantageous, it 

 becomes important to learn just how far the advantage ex- 

 tends; and we find that mimicry is not of universal effective- 

 ness. Even the highly protected Heliconiinse and Danainse 

 are food for some predaceous insects. In this country, as 

 Judd has observed, the drone-fly (Eristalis tenax), which 

 mimics the honey bee, is eaten by the kingbird and the phoebe ; 

 the kingbird, indeed, eats the honey bee itself, but is said to 



