256 THE ENTOMOLOGIST’S REGORD. 
he witnessed in June, 1867, at Hartlepool. He first observed an 
unusual number of white butterflies in the street, about 9 a.m., and 
their numbers steadily increased ; by noon they were flying in hundreds, 
and at 2 p.m. there were thousands of them to be seen at once, all 
flying in one direction, viz., from east to west. They continued to pass 
in undiminished numbers till towards 5 o’clock, when a sudden 
thunderstorm and very heavy rain came on. Such of the butterflies 
as did not obtain shelter were quickly driven to the ground where they 
were pelted to death by the rain, and floated in hundreds along the 
flooded channels. When the rain ceased the day was too far advanced 
for flight to be resumed, and next day, although there was a large 
number about the streets, they flew in a desultory manner and entirely 
without the steady purpose-like flight of the day before. Hnquiry 
elicited that fishermen had seen the flight coming in from the open sea 
(where many had settled on the boats) which was perfectly smooth, 
and one or two had noticed that they rested on the water and rising 
again therefrom had pursued their flight. Robson calculated that the 
denser portion of the column was about 100 yards wide, although 
stragglers extended much further on either side. The length must 
have been very great, for the butterflies continued to advance from 
9 a.m. until 5 p.m., and had not commenced to decrease in numbers 
when the storm dispersed them. Cordeaux reports (Hntom., vil., p. 
161) that on the morning of June 4th, 1874, ‘very large numbers of 
Pieris brassicae and P. rapae, the latter, however, very greatly pre- 
dominating, came into the North Lincolnshire marshes from the 
Yorkshire coast of the Humber (which, at this point, is from four and 
a half to five miles across). or an hour that I was near the sea 
embankment they were constantly passing inland, flying, too, against 
a rather stiff south-west breeze. Looking towards the centre of the 
river with a strong glass I could distinguish flights of them far away, 
flickering in the blaze of sunlight against the grey background of water, 
like falling snowflakes. I remember a very similar immigration of white 
butterflies in the dry summer of 1870.’ Our own observation (supra) 
of the immigration of P. brassicae between Dover and Deal, took place 
in 1887, and the abundance of this species and P. rapae in the autumn 
of that year in Britain was extraordinary. Barrett records (Hnt. Mo. 
Mag., xxiv., p. 85) that towards the end of May, 1887, when walking 
along the top of the cliffs from Hunstanton to Old Hunstanton he 
came upon multitudes of P. brassicae (and to a less extent P. rapae) 
flying about the level ground on the top of the cliff, and settlng in 
dozens on the flowers, without appearing to be in any such numbers 
inland. As there were no fields of cabbage, turnips, &c., in the 
neighkourhood, he suspected that he had come upon a flight of 
immigrants immediately after their arrival. Adkin gives (Proc. Sth. 
Lond. Ent. Soc., 1899, p. 47) interesting details observed by himself 
and his daughter on July 27th, 1899, between EHastbourne and Beachy 
Head. On this morning, although white butterflies had not previously 
been very common, he noticed great numbers of Pieris rapae, large in 
size but poor in condition, fluttering over the furze on the upper part 
of the slopes, for the whole length of the down, the butterflies being 
left behind when the summit of the Head was reached. On returning 
to Eastbourne his daughter remarked that she had during the morning 
seen large numbers of white butterflies all flying in from the sea, and 
