

TOWER, DARWINISM. 425 
Stages possess mimetic values. They emphatically do not possess 
them, as shown by some individuals reared in 1906 at Orizaba. 
PROTECTIVE RESEMBLANCE. 
Instances of alleged protective resemblance in shape, pattern, 
color and form of Lepidoptera to leaves, lichens and other objects 
have been described in great numbers. The usual interpretation of the 
similarities in appearance between Lepidopterous form and coloration 
and parts of plants or other objects, is on the basis of the operation 
of Natural Selection. That is, it is assumed that the resemblance 
protects the possessor and makes attack by predacious enemies 
less frequent and successful; and that in any species showing this 
alleged protective resemblance, those less well protected by closeness 
of resemblance to the model are the ones eliminated. In consequence, 
a selective elimination operates constantly to bring about increased 
closeness of the resemblance. This sounds reasonable and is a 
plausible hypothesis that conceivably could account for the pro- 
duction of the very numerous cases of alleged protective resemblance. 
As far as I am aware, no serious effort has been made to discover 
whether elimination such as is assumed to take place, is an actuality 
in nature. There is another aspect of this protective resemblance 
that should be mentioned, although it cannot be discussed in this 
paper to the extent deserved; namely, whether or not the organism 
possessing this supposedly protective simulation habitually uses it 
for protection and concealment. 
_ The observations presented in the preceding section gave also 
a considerable body of information with regard to supposedly 
protectively colored Lepidoptera. Among the wings of eliminated 
butterflies. and moths collected in the twenty-two censuses in each 
of the ten Motzorongo locations, or from 220 censuses in all, a 
large number of wings of butterflies with leaf-patterns, leaf-shaped 
wings and so on were found. Corresponding to these collections 
of the eliminated, samples of the non-eliminated members of the 
protected butterflies were taken for comparison with the eliminated. 
The gross result for these 220 censuses over a period of years 
showed that the supposedly protected forms were largely eliminated 
in the adult state by spiders, ants and dragon-flies in the order 
