38 THE ENTOMOLOGIST. 



common, but their direction of flight not so marked ; and then 

 on to the sea front, where they were also in great abundance, but 

 they api)eared to be more inclined there to flit about among the 

 blossoms on the flowery banks, and I was unable to detect any 

 actually coming in from the direction of the sea. 



On the 28th, another very fine day, with a light south- 

 westerly breeze, I had another opportunity of closely watching 

 the butterflies. Along the parade banks, the sea front of the 

 Downs, in the gardens and even the streets in the town they 

 were swarming. Along the edge of the cliffs and the upper walk 

 of the parades, where the breeze caught them as they flew up 

 the banks, they looked just like a thick snow flurry driven by the 

 wind. I spent some time on the more sheltered banks en- 

 deavouring to estimate the proportions of the three species, and 

 arrived at the conclusion that P. hrassiae and P. rupee were at 

 this time in about equal numbers, with a sprinkling of perhaps 

 1 to 2 per cent, of P. napi; but by August 5th P. hrassicce had 

 become distinctly the commoner species. This was another very 

 fine day, and so dense a crowd were the " whites " on the coast 

 that as one walked along the parade paths the butterflies looked 

 almost like a shimmering white cloud as they rose and fell in 

 their flitting over the flowers growing on the banks. 



The morning of August Gtli was hazy, but the sky free from 

 cloud ; this gave enough sunshine to bring the butterflies out, 

 but they were somewhat sluggish, and more inclined to sit about 

 on the flowers than to take extended flights. I was thus able to 

 examine their condition carefully, and found that the great 

 majority of both P. hrassicce and P. rapce, although seldom 

 chipped, were largely more or less worn and dull looking as 

 compared with what few really fresh individuals there were 

 among them, the latter species being the more worn of the two. 



From this time the aggregate numbers decreased, somewhat 

 rapidly at first, and then gradually diminished, P. rapce at first 

 showing the more marked decrease, but by the middle of 

 September fresh specimens of both species were appearing 

 suggesting a third emergence, and for a time P. rapce appeared 

 to be again the commoner, but there was no repetition of the 

 great abundance noted at the end of July and early August, and 

 P. rapce dropped out altogether early in October, but P. hrassicce 

 was met with frequently for a couple of W'Ceks later, the last 

 being seen on the 21st of that month. 



At the time when the abundance was at its height — the 

 latter part of July — quite a number of dead P. hrassicce were 

 picked up in the garden. Many of them that were examined 

 showed no signs of injury, the wings were seldom chipped, and 

 the bodies did not appear to have been crushed, but the general 

 worn and faded condition of the wings suggested that these 

 individuals had been long on flight and had come to the natural 



