THE SCOTCH ARGUS 
57 
The resemblance between the larvae of E. aethiops and 
E. tithonus is so close during their last stage that they might 
readily be mistaken one for the other. The chief difference 
lies in the fact that the hairs of the former have the apical half 
brown and the basal half whitish, while those of the latter 
are wholly whitish with diverging cleft tips; the ground 
colour of E. tithonus is sometimes tinged with greenish-yellow, 
and the lateral stripe is whiter and bordered above by a deep 
claret-brown line. 
When ready for pupation, the larva forms a slight hollow 
on the surface of the ground at the base of the grass, and 
spins a loose open network cocoon over itself, resting in a 
more or less upright position ; and finally pupates. Pupation 
usually takes place during the first half of July. 
Pupa. Lateral view : It measures 127 mm. long, is rounded 
in shape and stout in proportion. Head and thorax are 
rounded, the abdomen is abruptly tapering, the cremaster is 
decurved, the wings are ample and swollen at the middle. 
The whole surface is finely granulated and, excepting the 
wings, is sparsely sprinkled with minute stumpy bristles. 
The general colouring is ochreous with a greyish hue over the 
middle of the wing ; the margin of the wing is yellow- 
ochreous ; the abdomen is amber-ochreous ; down the back are 
three amber-brown stripes and a fainter lateral stripe of the 
same colour. It remains in the pupal state for sixteen days. 
Imago. Average expanse of wings : male 45 mm. ; female 
50 mm. Sexual difference is distinct. Male .—The ground 
colour is a rich deep velvety-brown, the fore wing has a deep 
rust-red transverse band near and parallel to the outer margin, 
it is narrowed across the middle, and at the lower end ; it 
encloses three white-pupilled, velvety-black spots, and a very 
small black spot in the centre. The hind wing has a narrower 
band of the same colour and similar ocellated spots. The 
base of the fore wing and the discoidal cell, as well as the 
basal half of .the hind wing, are clothed with cilia. Under 
Side. The fore wing is paler in ground colour, the band is 
brighter, otherwise it is similar to the upper side ; the hind 
wing is a deep chocolate-brown with a lilac-grey sub-marginal 
band, the basal third of the wing is lighter brown, the dark 
brown ground colour forms a broad median band. 
