IQ 2 ENTOMOLOGY 



Mylothris pyrrha. the female of which imitates Heliconius numata. He 

 traces the transition chiefly through the males of several pierid species 

 for the males, though for the most part white (the typical pierid color), 

 "show on the under surface, though in varying degrees, an approach 

 towards the Heliconiine pattern that is so completely imitated by their 

 mates. These partially developed features on the under surface of the 

 males enable us to trace the history of the growth of the mimetic pattern." 

 Starting from Pieris locusta, it is an easy step to Mylothris lypera, thence 

 to M. lorena, and from this to the mimetic M. pyrrha. "Granted a 

 beginning, however small, such as the basal red touches in the normal 

 Pierines, an elaborate and practically perfect mimetic pattern may be 

 evolved therefrom by simple and easy stages." 



Furthermore (in answer to the second question), it does not tax the 

 imagination to admit that any one of these color patterns has at least 

 occasionally been sufficiently suggestive of the heliconid type to pre- 

 serve the life of its possessor; especially when both bird and insect were 

 on the wing and perhaps some distance apart, when even a momentary 

 flash of red or yellow from a pierid might be enough to save it from 

 attack. 



It is highly desirable, of course, that this plausible explanation should 

 be tested as far as possible by observations in the field and by experiments 

 as well. 



Mimicry and Mendelism. The weight of evidence is at present 

 vastly in favor of the theory of mimicry as against any other explanation 

 of the facts, even though the theory is sometimes stretched to impossible 

 limits by some of its enthusiastic adherents. The only opposing opinion 

 that has sufficient plausibility to demand much consideration as yet 

 is that of Punnett. 



In India and Ceylon the butterfly Papilio polytes has in addition to 

 the normal female a second form of female which mimics P. aristolochia 

 and a third which imitates P. hector; polytes being palatable to birds 

 and its two models unpalatable. 



This case, described by Wallace almost fifty years ago, is one of the 

 classic examples of mimicry. Punnett holds, however, that these re- 

 semblances are of no practical value and that natural selection has played 

 no part in the formation of these polymorphic forms and suggests that 

 Mendelism offers a better explanation of the phenomenon a suggestion 

 that should be tested experimentally. 



Adaptive Colors in General. Several classes of adaptive colors 

 have been discriminated and defined by Poulton, whose classification, 



