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irregularly placed, and often misshapen and deficient in 
pigment, the membrane of the wing showing between them, 
so as to give the insect a shining ‘‘greasy’’ appearance. Of 
course the three were more or less combined in many cases. 
Also he thought that in general the principal changes were 
produced along the margins and at the base and apex, and 
often along the nervures of the wings; perhaps there was 
some connexion between this and the fact ascertained and 
lately published by Mr. Mayer, that these were the parts of 
the wings in which the pigment was the last to develop. In 
conclusion, he called attention to the experiments of Mr. E. 
Fischer, of Zirich, and particularly to the considerable 
effect caused by brief exposure to a very low temperature, 
one gradually reduced from about 20° C. (68° F.) to 2° C. 
(28-4 F.), where pup of V. wrticw were kept for brief periods, 
causing more than half of the butterflies from them to be 
materially changed in appearance. 
Mr. Tutt exhibited a long series of insects, including 
specimens of Ascalaphus, collected by Dr. Chapman at 
Cannes during March, and by himself at Digne during April, 
1897, and remarkable for their early emergence. 
Paper, FPavhibitions, and Discussion on Mimicry. 
Dr, Dixry read a paper on ‘‘ Mimetic Attraction.”” He 
began by pointing out with the aid of diagrams that the 
process of mimetic assimilation might start from a given 
point and proceed along several divergent paths. For 
example, from an ordinary non-mimetic form of neotropical 
Pieris, such as Pieris phaloe, not one only but several diver- 
gent series of mimetic modifications could be traced; each 
passing through a graduated series of closely-allied forms 
until it terminated in a Peris or Mylothris bearing a more or 
less intimate relation with some protected form or forms of 
entirely different affinities. Such were the series leading 
through P. calydonia to P. demophile 2, a mimic of Aeria 
agna ; the series starting from 1’. demophile and passing into 
forms such as 7. locusta 2, which was in mimetic relation- 
