THE PALE CLOUDED YELLOW 
325 
and damp of that season is fatal to this species, and it becomes 
exterminated in this country until a fresh arrival of immi¬ 
grants reaches our shores from the Continent. Consequently, 
it may be for long periods before this butterfly again makes 
its appearance in any number in the British Isles. It is 
doubtful whether C. hyalc larvae ever reach hibernation in 
this country, except perhaps in the extreme south-western 
districts during exceptionally mild weather. The flight of 
this butterfly is swift and powerful, enabling it to accomplish 
with ease the passage over the Channel. Upon its arrival 
on our shores it has not far to seek before finding its favourite 
haunts, such as fields of Lucerne and Clover, especially those 
in bloom, which supply them with nectar to refresh them¬ 
selves after their journey. Both these plants furnish the main 
food of the larvae, therefore soon after their arrival the 
butterflies lay their eggs upon them. 
Haunts. The coastal counties are the chief haunts of the 
Pale Clouded Yellow, but sometimes it wanders far inland, 
and may be met with flying rapidly over downs and open 
country, probably in search of its favourite fields. It occa¬ 
sionally ranges to the northern counties, but it does not occur 
in Scotland or the Isle of Man, It visits Ireland in the years 
when abundant in England. 
The Egg. The eggs are deposited singly on the leaves of 
its food plant, standing erect with the base embedded in a 
thick patch of gluten, and adhering firmly to the surface. The 
egg is 1 *io mm. high, and is attenuated at both ends and of 
an elongate-ovate form ; there are from nineteen to twenty-two 
longitudinal keels and the intervening spaces are delicately 
ribbed transversely. When first laid the colour is a yellowish 
pearl-white. It gradually deepens in hue, however, and 
finally becomes a clear rosy-orange with the summit and base 
transparent white and glassy ; just before hatching, it turns 
to a purplish-lead colour. On August iSth, 1900, I captured 
a female C. hyalc which laid 236 eggs on Clover plants during 
the following few days ; these commenced hatching on August 
29th, the egg stage lasting ten days. The full complement of 
eggs laid by C. hyale number about 500. 
Egg Laying. I have observed this butterfly depositing its 
eggs in a wild state, in Kent, as late as September 20th. 
