NATURE NOTES 
1 14 
Elm ; but the ordeal for the caterpillar and chrysalis amongst 
legions of sparrows would be great. 
The Painted Lady [Cynthia Carditi) might also be tried. 
This, like the above-mentioned, hybernates, and its larva feeds 
on thistles, preferring those that grow singly in open park-like 
ground ; but unfortunately on its food plant it is only too 
easily seen. 
As, however, by this time these butterflies have laid their 
eggs, some larvae might be laid down ; and to any London 
Selbornian willing to undertake the task of placing them in 
suitable spots, I will endeavour to forward a small supply. 
To ensure success some trouble should be taken in selecting 
the feeding ground. On a patch of nettles at the side of the 
field in front of my house the larvae of Vanessida are to be 
found by the thousand almost every year. This is an exposed 
spot and away from the fatal drip of trees. Close to this, 
nettles grow most luxuriantly on a long bank, but the butter- 
flies never resort to them, as they are shut out by trees from 
all but the early morning sun. I have never noticed birds 
attack these larvae, but whether the London sparrow be more 
venturesome in this respect than his country cousin, time may 
possibly prove. Methinks the foes awaiting the caterpillars on 
a nettle bed will be human rather than passerene. 
Some of the Hair-streaks and Blues are also worth 
consideration. 
In the centre of Bury St. Edmunds, where of course there 
are many sparrows, there is an elm tree on which the White 
W. Hairstreak [Theda W - Album) is to be seen every year. 
Where it occurs its numbers are often great. 
The Holly Blue [P. Argiolus), so-called because its larva 
feeds on the flowers of the holly, may also be suggested. I 
do not think this insect would stand a journey by post, but it 
has the recommendation of being double brooded. 
As to the Common Blue [P. Alexis), there would be great 
danger of its larva being trampled to death, or eaten with its 
food plant. 
In attempting to introduce Lepidoptera into London, there 
is a probability that they would be comparatively free from the 
attacks of their greatest foes, ichneumon flies, whose absence is to 
be expected from places where their natural prey does not exist. 
A very small ichneumon fly lives by the dozen as a grub in 
a butterfly’s egg. Sixty or seventy of a larger kind make their 
living off a caterpillar, while a third species lays numerous eggs 
in a chrysalis. 
London Selbornians sometimes tell us in a delightful way 
through the pages of N.\ture Notes of the creatures still left 
to them for observation, and would be the first to rejoice in 
adding a few more butterflies to their scanty list. 
Edmund Thos. D.vubeny. 
Market Weston, Thetford. 
May, 1901. 
