MIGRATION 
25 
rest, to rise again with as much apparent ease as from the 
land, and resume their journey to their intended destination. 
But I have recorded instances of this great American 
butterfly having been introduced into England by shipping. 
In the cases recorded, the butterflies have been brought over 
to this country in ships, having been shut up in the holds 
when the hatches had been closed down. When the hatches 
are opened upon arrival in port, the butterflies have been 
seen to fly t out. 
The time of arrival of certain immigrants varies according 
to the species. The Camberwell Beauty apparently never 
arrives on our shores before July, and usually not before 
mid-August ; also the Milkweed is generally an autumnal 
visitor, rarely occurring before September. The Painted 
Lady and the Red Admiral usually arrive during the latter 
part of May or early in June, when also the f ; rst immigration 
of the Clouded Yellow and the Pale Clouded Yellow takes 
place. Also the Queen of Spain Frit illary has occasionally 
appeared in the spring. 
In certain years vast invasions of the Painted Lady have 
occurred in late autumn. Such was the case in the record wet 
year of 1903, when, during the last ten or twelve days of 
September, immense swarms reached our eastern coast and 
spread over the whole of the country. So vast was the 
invasion, that the swarm reached from the Shetland Islands 
to the extreme southern districts of both England and Ireland. 
This great flight lasted six days ; at the end of this time, 
when the flight of arrivals ceased, wherever observations were 
kept these butterflies swarmed in countless profusion in an 
unbroken line along the whole of the eastern coasts of England 
and Scotland. This species, like most of the other migrants, 
arrives from southern and south-eastern Europe. But the 
Camberwell Beauty is of Scandinavian origin, arriving from 
the north-eastern and eastern regions, while the only traveller 
from the west is the great American Milkweed butterfly. 
During migration, the direction of flight is not influenced 
by the wind, as it is proved that butterflies fly at times both 
against and with the wind, and even a change in the direction 
of the wind while migration is in progress does not influence the 
course of flight, unless, of course, the wind should rise to gale force. 
