bo 
ADAPTIVE COLORATION 
os 
Oo 
pick out the drones; chickens also discriminate between drones 
and workers, eating the former and avoiding the latter. Bum- 
ble bees and wasps, imitated by many other insects, are them- 
selves eaten by the kingbird, catbird and several other birds, 
though it is not known whether the stingless males of these 
are singled out or not. Such facts as these do not discredit 
the general theory of mimicry but point out its limits. 
Evolution of Mimicry.—Natural selection gives an adequate 
explanation of the evolution of a mimetic pattern. Before 
accepting this explanation, however, we must inquire: (1) 
What were the first stages in the development of a mimetic 
pattern? (2) What evidence is there that every step in this 
development was vitally useful, as the theory demands that it 
should be? ‘These pertinent questions have been answered by 
Darwin, Wallace, Muller, Dixey and several other authorities. 
The incipient mimic must have possessed, to begin with, col- 
ors or patterns that were capable of mimetic development; 
evidently the raw material must have been present. Now 
Muller and Dixey in particular have called attention to the 
fact that many pierids have at least touches of the reds, yellows 
and other colors that are so conspicuous in the heliconids. 
More than this, however, Dixey has demonstrated—as appears 
clearly from his colored figures—a complete and gradual tran- 
sition from a typical non-mimetic pierid, Pieris locusta, to the 
mimetic pierid 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 sur- 
face of the males [compare Figs. 2 and 3 of Frontispiece] en- 
able us to trace the history of the growth of the mimetic pat- 
tern.” 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, 
