The chrysalides are generally attached by the 'tail,' and further secured by a silken cord round the body, as we have already observed in the case of the Pieridæ.
The perfect insects differ from the preceding species in that all six legs are perfectly developed and adapted for walking.
There are only three genera in this large family:
- Thecla—The Hairstreaks, with 'tailed' wings.
- Polyommatus—The 'Coppers.'
- Lycæna—The 'Blues,' with wings either blue or brown.
The Brown Hairstreak (Thecla Betulæ)
The five Hairstreaks which constitute the genus Thecla are all pretty insects, characterised by hair-like streaks on the under surface.
Betulæ is the largest of these. Its upper surface is of a deep brown colour, with orange-brown marks at the anal angles of the hind wings, and, in the female, a large patch of orange on the fore wings. The under side ([Plate VI], fig. 3) is orange brown, much lighter in the male than in the female. On the fore wings are two
white lines, the inner one of which is indistinct; and on the hind wings are two others, the outer one being longer and more distinct than the inner.