100 
NYMPHALIDAE 
This beautiful butterfly was known in this country in 1710, 
when its occurrence in Cambridgeshire was made known. In 
1818 a large number of A. lathonia were seen and captured in 
various places in the southern counties. In 1868 it was again 
fairly common and thirty-three were captured. The greatest 
number taken in one year in this country was in 1872, when 
no less than fifty were captured, mostly in Kent. In 1880 
eighteen were recorded ; in 1882 twenty-five ; and eleven 
in 1883. In 1884 °nly three were seen, and one only in each 
of the following years, 1885, 1892, 1898, 1899, 1900, 1910, 
1921, 1928, and three in 1929 ; making in all only fourteen 
specimens during the last 50 years. 
This remarkable falling off in numbers in the last half century 
is extraordinary and unaccountable, un¬ 
less it may be due to the changed 
conditions of the opposite French coast, 
where A . lathonia was formerly abun¬ 
dant. Dover and the surrounding dis¬ 
trict has always been the chief and most 
productive locality for this rare visitor. 
Hibernation. On the continent this 
species hibernates as a larva after its 
second moult. 
Egg Laying. On August 6th, 1903, 
illary 6 arrest Sketched 1 received a living female from Zermatt, 
from life. which 1 placed on a growing plant of 
Wild Heartsease (Viola tricolor). On 
the following day she laid about ioo eggs ; she survived for 
eight days longer, but no more eggs were deposited. They 
were laid on different parts of the plant and they all hatched 
on August 14th, lasting seven days in the egg state. 
Egg. The egg is 0*65 mm. high, of a rather straight-sided 
conical form, widest at the base. There are about forty 
longitudinal keels, irregularly formed and of various lengths, 
some not reaching half-way up the side, and others running 
the entire length from base to crown, where they terminate 
abruptly, and form a series of triangular peaks round the 
summit, surrounding the granulated micropyle ; the spaces 
between the keels are finely ribbed transversely. When first 
laid, the egg is of a very pale lemon-yellow colour, inclining 
