Lepidoptera The Speckled Wood Or Wood Argus Butterfly – Pararge Egeria
Most of our butterflies delight in the hot sun, and are to be seen on the wing only when it is shining brightly. This fact is particularly noticeable on a bright day with occasional heavy clouds. While the sun’s rays are pouring uninterruptedly on the landscape, numbers of these light-lovers are to be observed flitting about; but when the dense shadow of a passing cloud creeps over the ground they rapidly disappear from view, having settled down to rest on leaves and stems. Then, as soon as the shadow passes away, the air is again enlivened with their sports and flittings.
The Wood Argus is a marked exception to this rule. It delights in the cool shade of the narrow paths of woods, where it slowly flies up and down the lonely footpath, taking but little heed of strangers that intrude on its haunts, and seldom venturing into the full blaze of the sun unless pursued. Even on dull days it continues its solitary flight, and may even be seen on the wing while a soft rain is bathing the dripping foliage.
The upper surface of this pretty butterfly is shown on Plate V, fig. 5, and the under side in the accompanying woodcut. Both sides are prettily marked with various shades of brown and buff, and adorned with white-centred dark eye-spots which have earned for it the name of Argus.
It first appears on the wing in April, and may be seen from this month continuously to the end of August.
The food plants probably consist of many species of grasses, the cock’s-foot (Dactylis glomerata) and couch grass (Agropyron repens) being among the number, and the eggs are laid on or in the neighbourhood of these during the summer months.
The caterpillar of this species is of a dull greenish or brownish colour, and it has two whitish stripes (sometimes three) down the middle of the back, and similar stripes along each side. It hybernates during the winter, and is full grown in March, when it changes to a dull green or brownish chrysalis, which is streaked with black, and has a few white dots on the back.
It has been stated that the butterfly is on the wing from April to August, and, according to some authorities, there are no less than three broods during this time, following each other in rapid succession. It is common throughout England and Ireland, and is known in parts of Scotland.