insects in warmer countries may be double-brooded.  C.G.  Barrett records (1893, vol.  I. pp. 153-4) how in the August of 1879 hundreds and thousands of ‘Painted Ladies’ (Pyrameis cardui) migrated into the south of England from the European continent where in many places great swarms had been observed early in the summer.  ’These August butterflies, the progeny of the June swarms, coming from a warmer climate, had no intention of hibernating, but paired and laid eggs.  Some of the larvae were collected and reared indoors [butterflies] emerging in November and December, but out of doors all must have been destroyed by damp or frost, in either the larva or pupa state, for no freshly emerged specimens were noticed in the spring, and no trace of the great migration remained.’

In September and October the pedestrian, even in a suburban square, may see moths with pretty brown, white-spotted wings flying around trees.  These are males of the common ‘Vapourer’ (Orgyia antiqua), in search of the females which, wingless and helpless, rest on the cocoons surrounding the pupae whence they have just emerged, the cocoons being attached to the branches of the trees where the caterpillars have fed.  After pairing, the female lays her eggs among the silk of the cocoon, partly covering them with hairs shed from her body, and then dies.  The eggs thus protected remain through the winter, the larvae not being hatched till springtide, when the young leaves begin to sprout forth.  The caterpillars, adorned and probably protected by their ‘tussocks’ of black or coloured bristles, feed vigorously.  Their activity and habit of occasional migration from one tree to another, compensates, to some extent, as Miall (1908) has pointed out, for the females’ enforced passivity; only in the larval state can moths with such wingless females extend their range.  The caterpillars spin their cocoons towards the end of summer, and then pupate, the moths emerging in the autumn and the eggs, as we have seen, furnishing the winter stage.

After midsummer, the conspicuous cream, black and yellow-spotted ‘Magpie’ moth (Abraxas grossulariata) is common in gardens.  The female lays her eggs on a variety of shrubby plants; gooseberry and currant bushes are often chosen.  From the eggs caterpillars are hatched in autumn, but these, instead of beginning to feed, seek almost at once for rolled-up leaves, cracks in walls, crannies of bark, or similar places, which may afford winter shelters.  Here they remain until the spring, when they come out to feed on the young foliage and grow rapidly into the conspicuous cream, yellow and black ‘looper’ caterpillars mentioned in a previous chapter (p. 60).  These, when fully-grown, spin among the twigs of the food-plant a light cocoon, in which the black and yellow-banded wasp-like pupa spends its short summer term before the emergence of the moth.