244 LYCAENIDAE 
weeks of July, when the females are fully out and in the 
finest condition. 
In 1895, when nothing was known relating to the later 
stages of the life of this butterfly, I then endeavoured to 
solve the mystery surrounding the last stage of the larva, 
and pupa, of this remarkable insect, but it was not until 
twenty years after, and after endless research that success in 
solving the problem was at last forthcoming. This achieve¬ 
ment would probably have failed without the unlimited, 
invaluable, and generous assistance of my friend Capt. E. B. 
Purefoy, who thoroughly investigated every detail of its 
history, after the final moult of the larva, so completely that 
the whole of its wonderful life history was clearly revealed. 
Owing to the limited space here provided, I can only briefly 
describe the life history in these pages, therefore, for a 
complete detailed account of the very remarkable life of 
M. arion in its various stages, I must refer my readers to my 
former work, Natural History of British Butterflies, Vol. II, 
PP- I 37 ' I 49 - This beautiful butterfly occurs only in localities 
where Wild Thyme ( Thymus serphyllum ) grows in abundance. 
The blossoms of this plant form the sole food of the larva during 
its short existence above the surface of the ground, and the 
butterfly deposits its eggs only on the flowers, which also 
comprise the chief food of the butterfly. 
Egg Laying. In 1902, from July 5th to 17th, inclusive, I 
watched several females laying their eggs on the flower- 
heads of Wild Thyme growing in various situations, from the 
summit of the hills to the depths of the valleys, also on the 
prolific growth of Thyme covering the turf walls. Under 
every plant of Thyme I found ants in abundance, and noticed 
several females selected the Thyme covering the ant hills. 
I therefore arrived at the conclusion there was some close 
connection between the larvae of M. arion and ants, as it 
was well known that symbiotic habits existed between ants 
and certain Lycaenid larvae. This is due to the fact that 
the ants obtain nourishment and pleasure by feeding on the 
sweet fluid excreted from the honey-glands of the larvae, 
while the latter are afforded protection from their natural 
enemies by the attendant ants and in the case of M. arion 
the larva of this butterfly feeds, during its last stage, 
