THE ABUNDANCE OF WHITE BUTTERFLIES IN 1917. 39 



end of their existence. It is true that the species was attacked 

 by birds also : as an example, it was no uncommon occurrence 

 to see a blackbird {Turdas merula) seize a butterfly and strut about 

 on the grass with it in its mouth, but in such cases the wings 

 only were to be found afterwards. 



On July 29th a thunderstorm broke up the weather, and 

 for some few days it became very unsettled, with frequent periods 

 of heavy rain, but even this did not keep the butterflies quiet. 

 On several occasions quite a number of them were seen on the 

 wing in the garden while rain was falling, and had been falling 

 for some time. So restless were they that if there had been 

 even a gleam of sunshine in the morning to rouse them from 

 their night's rest, they seemed incapable of again settling down, 

 at any rate, for a long time after the sky had clouded over and 

 rain was falling. 



I have already referred to P. rapce resting on a Weigela shrub, 

 the leaves of which had turned a sickly yellow colour*, with which 

 the under sides of the butterflies matched so well that it was 

 with some difficulty that they could be detected ('Entom.,' 1917, 

 p. 191). This I found to be quite a habit with the species ; on 

 practically any evening that I looked at the shrub dunng the 

 period when the butterflies were so very abundant, I found from 

 three to half a dozen so resting, and on one occasion, when 

 during the day the sky had become densely overcast, I counted 

 nine individuals so settled down, and it is quite possible that 

 even then 1 bad not detected all that were there, so difficult were 

 they to see ; yet during all the time I found only one P. rapce 

 settled on the adjoining shrubs, which included a couple of other 

 Weigelas, but which still had green leaves. 



Along the road, which borders the garden on the north-west, 

 grows a long row of densely-foliaged elm trees, the side of 

 which next the garden therefore faces south-east and catches the 

 full force of the early morning sunshine. One morning, towards 

 the end of July, at about 6.15 (g.m.t.), my attention Avas attracted 

 by large numbers of white butterflies sitting on the side of these 

 trees nearest to the garden. It was evident that they had roosted 

 for the night in the trees, and had crawled out on feeling the 

 first warmth of the early morning sunshine, and were sunning 

 themselves preparatory to taking flight, which did not appear to 

 take place until an hour or more after the butterflies first showed 

 themselves on the trees. The species appeared to be chiefly, if 

 not entirely, P. hrasdcce, and the performance was repeated on 

 several mornings, 



(To be continued.) 



