lxxv, lxxvi] ( Hs) 
CuamMpPion said that he had noticed specimens of Gonepteryx 
rhamni seek the under-sides of bramble leaves. 
Dr. T. A. CHapman said that Col. Yerbury’s observation on 
Euchloé euphenoides resting on the flowers of Biscutella is one 
that may be often made in the South of France, and few 
English Entomologists have not observed 7. cardamines at 
rest on Alliaria flowers, or on some Umbellifer that roughly 
resembles it. These facts seem to give the clue to how the 
practice of these Crucifer-feeding Pierids of affecting objects 
of their own colour for resting arose. In so many of these 
cases, the food-plant is in flower when the butterfly is on the 
wing, and in the case of Huchloé the flower head is the 
place selected for egg-laying. It comes about, then, that the 
butterflies frequent the flowers of their food-plant, both for the 
honey they afford and for egg-laying. That it would often 
happen, therefore, to be the resting-place of the butterfly 
when overtaken by a sudden failure of sunshine is obvious. 
Nothing further is needed as a basis for natural selection to 
gradually accumulate in association, the characters of resting 
on the flower of the food-plant, and assimilation to it in colour. 
A butterfly, searching for a flower head to rest on, will act 
of course in the same way as one searching for it for any other 
_ purpose, viz., it will discover at a distance an object of the 
desired colour, and will be able to verify what it really is, 
only after a close approach. If it wants to suck honey, or to 
lay an egg, such verification is imperative, and all collectors 
are familiar with butterflies closely approaching a piece of 
coloured paper, a dead leaf or other object, and only when 
quite close discovering that it is not the desired mate, or 
flower, and at once departing. But if a resting-place for the 
night is desired, such verification is not absolutely essential, 
and a place must be chosen, so that if after several tries a 
near approach only produces disappointment, an occasion at 
length occurs, when advancing evening makes it necessary to 
appropriate the resting-place without the final verification. 
Thus a Pieris or a Luchloé will learn to accept as a resting- 
place any white object, even if it be not a flower head of a 
Crucifer. 
But if it be objected that cabbage and turnip, the usual 
