(selva 4) 
prominent in this species and is distinctly blue in colour, it 
is very long, tapering, slightly wider at the centre, whence it 
tapers down slightly to the apex which terminates in a blunt 
point—it is the widest scale of this type that I am acquainted 
with and is very plentiful all over the basal half of the wing, 
getting less so towards the termen. The “ blasenschuppen ” 
are large, almost oblong in shape, with a comparatively 
short attachment peduncle; they have usually ten rows of 
reticulations but go up to twelve. 
In Polyommatus icarus the costal cable of fringe-like scales 
is not nearly so heavy and prominent as in argus (Linné) and 
at the basal area is largely mixed with the long hairs found in 
that area though these become brown on the costa whilst 
they are whitish elsewhere, the other scales differ in very 
minute particulars, showing the near relationship of the two 
species; they are however simpler in pattern and have more 
or less evenly terminated apices; the ‘ blasenschuppen ” 
exhibit a marked divergence, for in this species they are 
elliptical in shape tapering at the base slowly into the stem- 
like attachment, and have but six rows of dotted reticulations 
instead of eleven. In addition to the basal hair-like scales 
is another somewhat similar one, but much thicker, it is better 
developed in thetis and will be described under that species. 
Polyommatus semiargus has scales throughout entirely of 
the icarus type, differing only in size more than actual shape, 
the thick hair-like pattern being very close to that species. 
The “blasenschuppen”’ follow closely the zcarus pattern, 
being a long oval, slightly wider than in that species, and with 
seven rows of reticulations, though in one scale I counted eight. 
In Polyommatus thetis the scales show some advance in 
development, in the basal area some of the blue ones have 
scalloped, whilst a few have waved apices, but the large 
majority of the blue scales are approaching the simpler 
pattern found so largely, as I shall show hereafter, in the 
brilliantly blue exotic species; this I am inclined to regard 
as a later development than the highly serrated scales of the 
brown and non-metallic blue species, in this case they have 
not the absolutely evenly arched apices but a very close 
approximation to that character, the distal end, though 
