Lepidoptera The Peacock Butterfly – Vanessa Io
This is another of our commonest and most beautiful butterflies. Its general appearance is such that it cannot possibly be mistaken for any other. The upper side (Plate IV, fig. 1) is rendered conspicuous by the beautiful eye-like marks at the costal angles of all four wings; and the under surface is very richly decorated with a fine arrangement of black and dark-brown patches and streaks.
Io is very abundant in all parts of England, and is well known in many parts of Scotland and Ireland, but seems to be rare in the extreme north of both of these countries.
Its food plant is the stinging nettle (Urtica dioica), and on this the eggs are laid in April by females that have hybernated during the winter.
The caterpillar is full grown at the end of June or beginning of July. It is black, with numerous minute white wart-like projections. Its spines also are black, and its claspers brown.
The chrysalis may be found suspended by the tail on some object in the neighbourhood of the food plant, or sometimes on the food plant itself. It is of a greenish colour, with yellowish patches, but turns darker as the time approaches for the emerging of the perfect insect.
This event takes place in August, and the butterfly, after a brief period on the wing, seeks out a sheltered spot for its winter nap.