The eggs are laid in May by females that have hybernated through the winter, and the caterpillars may be found feeding during July and August.
The caterpillar is coloured grey and brown, with a black head, and a broad white stripe down the back of the hindermost segments. The body is armed with a number of spines, some of which are white, and others pale brown.
The chrysalis is a very peculiar object, having two ear-like projections extending forwards from the sides of the head. It has a number of angular projections, and is of an umber-brown colour, finely netted with black lines, and having several spots of a brilliant metallic lustre.
The Large Tortoiseshell (Vanessa Polychloros)
Our two tortoiseshells—large and small—are very similar in their colour and markings, and moreover are not always to be distinguished by their size, for specimens of the larger species are sometimes even inferior in this respect to the largest of the smaller species; so, to avoid all risks of mistaken identity, we must look for more reliable marks of distinction between them.
The present species is figured on [Plate III] (fig. 8), where it will be seen that the ground colour of dark tawny brown is spotted and bordered with black. The border of the hind wings contains a row of crescent-shaped blue spots. The costal margin of the fore wings, between the black patches, is decidedly lighter than the general ground, and is yellow rather than brown. It will be noticed, too, that a black spot lies very near the anal angle of these wings.
The under surface, though by no means brilliant, exhibits a rich blending of various shades of brown.
This butterfly is not known to occur in either Scotland or Ireland, and is by no means common in England. Its chief localities are in the midland and eastern counties.
The perfect insect generally appears about the middle of July, and after spending a month or six weeks on the wing, seeks out a sheltered spot in which to spend the winter. In the spring—April or May—it again takes to flight, and during the latter month the females are busily engaged in the deposition of their eggs.