Читать книгу The Butterflies of the British Isles - Richard South - Страница 18

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This butterfly is not often seen away from its favourite haunts in the country; these are woods, especially the sunny sides, leafy lanes, and even marsh land. As in the case of the two Whites previously noticed, there are always two broods in the year. The first flight of the butterflies is in May and June, occasionally as early as April in a forward season. These specimens have the veins tinged with grey and rather distinct, but are not so strongly marked with black as those belonging to the second flight, which occurs in late July and throughout August. This seasonal variation, as it is called, is also most clearly exhibited on the under side. In the May and June butterfly (Plate 13, left side) the veins below are greenish-grey, and those of the hind wings are broadly bordered also with this colour. In the bulk of the July and August specimens (Plate 13, right side) only the nervures are shaded with greenish-grey, and the nervules are only faintly, or not at all, marked with this colour.

Now and then a specimen of the first brood may assume the characters properly belonging to the specimens of the second brood; and, on the other hand, a butterfly of the second brood may closely resemble one of the first brood. As a rule, however, the seasonal differences referred to are fairly constant. By rearing this species from the egg it has been ascertained that part (sometimes the smaller) of a brood from eggs laid in June attains the butterfly stage the same year, and the other part remains in the chrysalis until the following spring, the butterflies in each set being of the form proper to the time of emergence.