Scotch Argus.
8, 11 male (Scotch); 9 do. (English); 10, 12 female (Scotch).
The chrysalis has the body ochreous, with a darker stripe down the back, and other lines; the eye covers are black, and the thorax, antennæ cases, and wing covers are dingy, dark purplish-brown.
The above descriptions of caterpillar and chrysalis are adapted from Buckler, whose figures of these stages are also reproduced on the plate.
Aira præcox, A. cæspitosa, and Poa are the grasses that seem to be the food of the caterpillar.
Mr. Haggart, of Galashiels, who had exceptional opportunities for observing the habits of this butterfly in its natural home, gives a most interesting account of it in the Entomologist for November, 1895. He writes—
"The haunt of this species is, almost without exception, the margin of a plantation or wood where the different species of Poa grow abundantly, and always situated in such a position as to receive the first rays of the rising sun. This last-mentioned fact is so plainly evident, that the least observant cannot fail to notice it. The insect is truly sun loving, and no collector need go in search of it with any thought of success if the day be dull.
"It is most interesting to observe the extreme sensibility of the insect to shine and shade. A very good day to illustrate this is one when heavy clouds at intervals obscure the sun; the moment it disappears so also does the butterfly, and no sooner does it shine forth again than, as if by magic, scores of the insect are on the wing.
"The under side of the insect bears a marked resemblance to that of a dead leaf, and I have often watched the males being deceived by withered leaves lying among the moss. They would flutter down quite close to the leaf, immediately rise with a disappointed air and fly a little further, only to be deceived again and again.
"The ova are deposited amongst the Poa grass, and hatch in September. Towards the end of October the larvæ go down and hibernate throughout the winter and spring, coming up to feed again in May; they are generally full-fed about the end of June; and the insect appears in July or August. The larvæ are nocturnal feeders, coming up to feed on the grass just about dusk. The method of procuring the larvæ is by no means enviable, even to the most ardent entomologist, as in the uncertain light it necessitates crawling on one's hands and knees amongst the grass, and there is always the risk of grasping those little brown slugs in mistake, which resemble the larvæ very much in shape and colour. No artificial light can be used, as the larvæ immediately drop down amongst the grass if this is done. The only alternative, therefore, is to use one's eyes to the best advantage until the darkness makes that impossible.