1 66 THE BOOK OF BRITISH BUTTERFLIES. 



in suitable situations up and down England where this 

 butterfly may be taken, yet it is well worth capturing, 

 for it can seldom be described as common. It is 

 present in Ireland, but does not appear to be found 

 in Scotland. 



The eggs are laid in the autumn in September or 

 even October and are firmly attached to the twigs of 

 the food-plant. They remain unbroken till the spring, 

 when the young larvae appear, and feed in May and 

 June, at the end of which month or beginning of the 

 next the pupae may be found. The imago is on the wing 

 from July till September, sometimes continuing even 

 into October. 



The larva (Fig. 180) is woodlouse-shaped, the dorsal 

 surface being arched and sloping abruptly towards the 

 head, but gradually towards the anal extremity. The 

 sides are very much dilated towards the ventral surface, 

 and the brown head is retractile within the second seg- 

 ment. The segments are deeply and clearly separated 

 from one another. The dilatation and dorsal ridge bear 

 pale, stiff hairs. The ground-colour is bright green, 

 marked with two whitish-yellow lines on each side and 

 two oblique lines of the same colour on both sides of 

 each segment. One pair of lines is dorsal, and the other 

 pair runs along the dilatation below the yellowish-white 

 spiracles. The ventral surface, legs, and claspers are 

 greenish. The caterpillar, from which this description 

 was made, a day or so before turning became pale ashen- 

 purple in ground-colour while the markings became quite 

 white. 



The pupa (Fig. 181), which sometimes at least is un- 

 suspended and has the last skin attached to the anal 

 extremity, is short, unangled, and dark brown in colour. 

 The wing-cases and anterior extremity are freckled with 



