MIMICRY 
533 
of mimicry compel the inference that insectivorous birds, and pos¬ 
sibly lizards, appreciate comparatively minute differences of shape 
and colour, yet it is quite conceivable that they cannot distinguish 
these at a greater distance than a myopic man. We know even less 
about the sense impressions of insects, in spite of the patient 
observations of Forel and Lubbock, and the brilliant experiment of 
Exner. The whole subject is discussed in detail by Dr. Auguste 
Forel, who seems to have established the fact that insects have a 
very keen perception of movement—possibly far more acute than 
their sense of form and colour. -1 It has often occurred to me when 
collecting butterflies that it is just possible that they can smell a 
collector as far as they can see him. 
Some opponents of mimicry seem to think that they have proved 
their case when they declare that model and mimic can be distin¬ 
guished, or when they cite cases of birds attacking distasteful species. 
Since the last paragraph was written powerful attacks upon the 
whole theory of mimicry have appeared. Those of Col. FT. Manders 
deserve special attention on account of the wide experience of their 
author. His chief point is that he denies that birds exercise 
discrimination in their attacks on butterflies. 1 2 I agree with 
Professor R. C. Punnett, 3 that the first steps towards mimicry 
present great difficulties, but I fail to see that Mendelism has 
any light to throw on the subject. It is remarkable that Professor 
Punnett, whose power of diagnosing insects on the wing appears to 
be exceptional, should nevertheless have been deceived by the re¬ 
semblance to Butterflies of a Dragon-fly (Rhyothemis variegata , 
Johanns.), and a Homopterous Bug (Hansenia glauca, Kirby). As 
regards the latter, which I saw two or three times at Kandy, I have 
a note: “very blue on the wing, but flight much slower than a 
Lycaenid.” Again, is Professor Punnett justified in his assumption 
that a bird reasons about the flight of a butterfly in the way that a 
scientifically trained naturalist does ? Such severe criticisms as these 
two authors have published cannot but increase our knowledge of a 
difficult subject, but the coup de grace has not yet been delivered. 
Once more it must be repeated that no supporters of the theory 
claim that the disguise is never seen through, nor do they claim that 
distasteful species are never eaten. In the severe struggle for 
1 Forel, “ The Senses of Insects.” Translated by Macleod Yearsley, 1908, passim. 
2 Manders, Trans. Ent. Soc. Land., 1911, pp. 417-425; also, Proc. Zool. Soc, 
Lond.y 1911, pp. 696-749. 
3 Punnett, Spolia Zeylanica , vol. vii., part xxv., 1910, pp. 1-24. 
