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JOURNAL oF VARIATION. 
Vor Xe Noset0. Octoser 151TH, 1900. 
Sey, 
AND 
Migration and Dispersa! of Insects: Lepidoptera. 
By J. W. TUTT, F.E.S. 
Besides the two species of Coliads (CU. edusa and C. hyale) and 
Pyrameis cardui, to which reference has already been made, Pieris 
daplidice, Argynnis lathonia and Muvanessa antiopa, also, can only be 
considered to be British species, so far as the immigrants themselves, and 
the direct progeny of these immigrants are, for the rest of the summer 
months directly following their arrival, able to exist here. The 
appearance of these species in this country is very uncertain, and their 
numbers always much fewer than those of the three first-named species, 
although in some years they are moderately abundant. It were 
perhaps useless to trace the years in which these species have occurred 
commonly in Britain. Generally, in such years, a few examples in the 
early summer are followed by an unusual abundance in autumn; 
suggesting that the former are the immigrants and the latter British- 
bred. At any rate these species exemplify well that particular group 
of insects that repeatedly become extinct in the higher temperate 
regions, and would never be seen in these districts were it not for the 
peegonal influx of immigrants. Stephens, in 1835, noted (Jllus. 
Haust., 1., p. 45) that ‘‘ till about the middle of the last century few 
BS ioae of 1. antiopa had been observed, but about 60 years since, 
it appeared in such prodigious numbers throughout the kingdom that 
the entomologists of that day gave it the name of the Grand Surprise. 
Of late it has again become infrequent; the last time that it occurred 
in plenty, according to Donovan, being in 1789 and 1803, a few only 
haying been captured subsequently. At the present day (1835) it still 
appears to occur occasionally throughout Mngland, as Mr. Backhouse 
informs me that it has been found repeatedly near Seaton, Durham, 
and often floating on the river Tees.” Wailes, on the authority of 
Backhouse, states that ‘‘about 1820 he saw vast numbers of this 
species strewing the seashore at Seaton-Carew, both in a dead and living 
state.” We may here point out that Hewitson notes (Mnt. Mo. 
May., ix., p. 161) that, on one occasion whilst crossing from Boulogne, 
he saw an example of this species midway in the Channel. In the 
year 1819 it was specially common in Durham and Suffolk, and in 
1846 in all the eastern and southern counties from Hampshire to York- 
shire and also in Ayrshire ; it was not uncommon in 1859-1860, but 
the greatest year for this species was 1872, when some hundreds were 
taken, its range extending, on this occasion, from Southsea and Dover to 
