The under side (Plate VI, fig. 6) is coloured with a delicate grey ground, adorned with a white streak on each wing, and a couple of orange spots near the anal angle of the hind wings. This species is very widely distributed, being common in oak woods in most parts of England, and also in many parts of Scotland and Ireland. It flies around the branches of the trees, and often disappoints the collector by keeping far beyond the reach of his net. [Illustration: FIG. 85.--THE PURPLE HAIRSTREAK--MALE.] Those in search of this pretty insect should ramble in oak woods, preferably in the south of England, during July and August. The eggs may be found glued to the twigs throughout the winter, and the larvae may be beaten from the branches of the oak in June. The colour of the caterpillar is brownish or pinkish green, with a row of V-shaped marks down the back. The chrysalis is of a brown colour, short and thick, and may be found either attached to oak leaves, or under the surface of the earth at the foot of the tree on which the caterpillar fed. _The Green Hairstreak_ (_Thecla Rubi_) Next to _Quercus_, this is the most plentiful of the genus. It frequents woods and heaths in nearly every county in England, and is also found in parts of Scotland and Ireland. It is peculiar among British butterflies as being the only one that exhibits a bright green colour. It also differs from the other Hairstreaks in two important particulars, for the hind wings, though angled at the hind margin, are not 'tailed,' and the characteristic hairstreak which gives the popular name to the genus is here represented only by a series of white dots across the wings, or, in some cases, by one or two dots on the hind wings only. [Illustration: FIG. 86.--THE GREEN HAIRSTREAK.] The upper side is dark brown, displaying metallic reflections when viewed in a strong light. The under side is represented in fig. 7 of Plate VI. The chief food plants of this species are the bramble (_Rubus fruticosus_), the birch (_Betula alba_), and the broom (_Cytisus scoparius_). The perfect insect flies in May and June, and the eggs are deposited during the latter month on the above plants. The caterpillars are full fed in July, and change to the chrysalis state towards the end of the summer. The colour of the caterpillar is pale green, with a yellow stripe and several white oblique lines along the sides, also a yellowish stripe down the back. The chrysalis is short and thick, and of a dark brown colour. _The Large Copper_ (_Polyommatus Dispar_)