218 
LYCAENrDAE 
marginal borders are much narrower than in those inhabiting 
damper peaty soils. Occasionally, the spots on the under side 
are confluent, forming streaks =ab. striata ; specimens have 
also occurred almost spotless =ab. obsoleta. 
This species varies greatly in size ; the males are usually 
the larger. As in other Blues, gynandromorphous examples 
sometimes occur. 
Genus ARICIA, R.L., 1817 
THE BROWN ARGUS 
Aricia agestis (Schiff., 1775) = astrarche. 
(Plate XX, facing page 225) 
This very active little butterfly, of rapid flight, darts 
about from flower to flower in brilliant sunshine. During dull 
weather and at night, it rests upon the flower-heads and stems 
of grasses and other rough growth, often assembled in little 
parties and occasionally in large numbers on the same plant. 
They are also frequently in company with the Common Blue. 
Haunts and Distribution. Rough, flowery hillsides and 
uncultivated fields, chalk downs with sheltered slopes abounding 
with various flowers and tangled vegetation, and especially 
where Rock-rose ( Hclianthemum vulgare) carpets the ground, 
are its favourite haunts. It is also found on sandy soils where 
Stork’s-bill ( Erodium cicutarium ) grows plentifully, as both 
of these are the natural food plants of the larvae. 
The Brown Argus is a generally common and widely distri¬ 
buted species throughout the southern half of England and 
Wales, becoming less numerous in the Midlands and northern 
counties, where it is represented by the intermediate form 
ab. salmacis ; while in Scotland its place is taken by the 
form ab. artaxerxes, common in various localities as far north 
as Aberdeenshire. In Ireland it apparently does not exist. 
Time of Appearance. — In England both forms of this butterfly 
are double-brooded ; the first brood is on the wing in May 
and June and the second emergence occurs in July, August, 
and early September. In Scotland.the form ab. artaxerxes is 
single-brooded only, and appears in July and August. 
