THE WHITE LETTER HAIRSTREAK 279 
butterfly in captivity for five and six weeks, the natural life 
in a wild state is not more than a month. 
Aberration. Aberration is chiefly confined to the size of the 
purple clouding in the female, and to the depth of colour ; 
very occasionally it is replaced by deep blue. A very rare 
aberration known as ab. bellus , Gerh., has an orange wedge- 
shaped mark at the end of the discoidal cell of the fore wing. 
Gynandromorphic specimens have occurred, but are very rare. 
Genus STRYMON, Hiibner , 1818 
THE WHITE LETTER HAIRSTREAK 
Strymon W-album (Knoch, 1782). 
(Plate XXXI, facing page 340) 
Owing to the remarkable shape of the egg of this little 
butterfly, which differs entirely from that of any other British 
Hairstreak, it should be generically separated. 
Haunts and Distribution. — The White Letter Hairstreak is 
very locally but widely distributed over the greater part of 
England and Wales. Its northern limit is apparently York¬ 
shire and it appears absent from Devon and Cornwall; in 
many of the remaining counties it is locally abundant, but 
it is most erratic in its appearance and habits. It appears 
in certain years in profusion in particular localities, usually 
flying high around Wych Elms; at other times it may be 
found in great numbers along the hedge-rows feasting on 
Bramble and Privet blossoms, and other flowers. In other 
years it may occur only in small numbers, flitting about the 
Elms. At times it has been found singly in districts where 
it has not previously been known. 
Its unusual abundance in certain years can be attributed only 
to beneficial climatic conditions, as this butterfly does not 
shift its habitat, A particular solitary tree, usually a Wych 
Elm, will remain its home year after year, 
The range of this species abroad extends throughout 
Europe, except for the Polar regions, and eastwards into 
Asia, Amurland and Japan. 
