28 o 
LYCAENIDAE 
Time of Appearance. This butterfly is single-brooded, 
appearing on the wing in July and August. It is very 
active, but its flight is short and rapid as it flits about the 
foliage. Like other Hairstreaks it has the habit of creeping 
leisurely over the leaves and branches. 
Hibernation. This species passes hibernation in the egg 
state, which extends over seven months. Eggs that are laid 
in July do not hatch until the beginning of the following March. 
Egg and Egg Laying. The eggs are laid singly at the forks 
of the small branches and twigs of the Wych Elm (Ulnius 
Montana), also but less frequently on the Common Elm 
( V . campestris). The egg is only 0*45 mm. high and 0’8o mm. 
wide. It is unlike the egg of any other British butterfly, being 
flat and button-shaped, with a projecting rim which is slightly 
convex. The upper surface of the rim is covered with very 
fine reticulations and minute spinous projections, which 
develop into a dense series of creamy-white points encircling 
the egg and forming the rim. All the reticulations are creamy- 
white and glassy. The ground surface is finely granular and 
of an olive-leaden colour. When first laid it is sea-green. It 
finally turns a clear chocolate ; previous to hatching, it changes 
to a purplish-drab. The egg stage lasts over seven months. 
Larva. The little larva makes its exit by eating a neatly-cut 
circular hole in the crown of the egg, just large enough for it 
to pass through, and immediately crawls away to feed on the 
expanding flower-bud. 
When fully grown, forty-five days old, and after the third 
and last moult, the larva measures 15*90 mm. in length. The 
segments are prominently humped dorsally, and there is a 
deeply-sunken longitudinal furrow down the centre of the 
back ; the first segment is rounded, compressed, and overlaps 
the head ; the sides are sloping and there is a dilated lateral 
ridge. The first segment has a central quadrangular, whitish, 
glassy disc. On the tenth segment is a dorsal transverse gland 
(videM. anon, description of honey-gland) similar in structure 
to the larval glands of many of the Lycacnidac , but I failed 
to induce it to exude any liquid, although it appears highly 
sensitive when touched, and instantly contracts. The gland is 
conspicuous only in the last stage of the larva. The whole 
surface of the caterpillar is densely covered with white, spinous, 
