Lepidoptera The Large Tortoiseshell Butterfly – 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 Butterfly PicturePlate 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.

The caterpillar feeds on the two species of elm (Ulmus campestris and U. montana), willow (Salix alba), sallow (S. Caprea), osier (S. viminalis), aspen (Populus tremula), and certain fruit trees; and is full grown about midsummer. It is of a tawny grey colour, with a black stripe on each side, and is covered with very small wart-like projections, and the spines are branched.

The chrysalis is of a dull pinkish colour, and may be found on tree trunks, palings, and walls, about the end of June, suspended from a silken carpet by means of its anal hooks.