THE ARTAXERXES BUTTERFLY. (Polyommatus Artaxerxes.)
([Plate XIV]. fig. 7.)
Colouring, same as in the last species (Agestis); but on the upper surface, the orange border-spots are often hardly perceptible on the front wing, and there is a distinct white spot in the centre of the front wings. The under side also is precisely like that of Agestis, with the black spots removed from the centre of the white rings, which are thus changed into large white spots, as shown in the figure.
There has been a great deal of discussion among entomologists, as to whether this be a distinct species, or only a variety of Agestis. I believe it to be the latter, but do not attach much importance to the question; and as this butterfly is found under the name of Artaxerxes, in almost every cabinet, and is rather a famous little insect, I have thought it best to give it a separate heading under its usual title, and collecting readers may still label it in their cabinet either as above, or as "P. Agestis, var. Artaxerxes," and probably will be equally right either way.
The popular nature and limited extent of this work will not, however, admit of the subject being entered into scientifically, and I can only here state that I have
seen specimens from various parts of the country, that include every intermediate variety between the ordinary Agestis of the south, and the Artaxerxes of Scotland. The Durham Argus, formerly called P. Salmacis, forms one of these gradations.
Against the idea of Agestis and Artaxerxes being one species, it has been objected, that the former is double, the latter single brooded. What of that? Plenty of species that are double-brooded in the south of Europe are well known to become single-brooded in a more northern situation.
The caterpillar is said to be exactly like that of Agestis. It feeds on Helianthemum vulgare (Rock Cistus).
The butterfly is found in July and August in several parts of Scotland, and the north of England. Arthur's Seat, Edinburgh, has been long noted for producing it.