364 
HESPERIIDAE 
gradually changes to ochreous-yellow. The egg stage lasts 
twenty-three days. 
Larva. Directly after emerging, the little larva feeds on 
the shell of the egg and eats all except the base, which adheres 
to the surface of the grass sheath. Soon after its meal, it 
starts spinning itself over with silk until it is completely 
enveloped in a little dense, elongated oval white cocoon, spun 
in the same spot where the egg was laid, so that the row of 
cocoons replace the eggs. In these compact, dense cocoons 
the larvae are completely hidden and protected during 
hibernation. Except for its near ally . 4 . acteon, this remark¬ 
able method of hibernation is unique among British butter¬ 
flies, and was unknown prior to my observations. 
The little larva awakens from its hibernation in the middle 
of April and eats its way out of the cocoon, and then 
commences feeding on a tender grass blade. After two or 
three meals, it draws together the edges of the blade of grass 
with cords of silk, and lies in the receptacle thus made. 
After the fourth and last moult the larva becomes fully 
grown and then measures 21 mm. in length. The head is 
globular and of an ochreous-green colour. The body is 
tapering at the ends and swollen in the middle. The anal 
segment terminates in a projecting flap. The colour of the 
body is grass-green with a rather darker dorsal band inter¬ 
sected by a pale line and bordered on either side by a pale 
yellowish line ; there is also a yellowish-white lateral stripe. 
Between the ninth and tenth, and the tenth and eleventh 
segments on the under surface is a patch of white, waxy 
substance. As in other larvae of the Hesperiidae which live 
in tubular dwellings, this species has an anal comb for the 
ejectment of its excreta (vide 0 . venata). The larval stage 
occupies 311 days. The larva is solitary. 
Pupa. The pupa is slender and tapering and measures 
from 16 mm. to 19 mm. in lehgth. The head is rounded 
and has a frontal conical beak-like point; the thorax is 
rounded and slightly sunken at the waist; the abdomen 
tapers gradually to the anal extremity, which terminates in a 
long, flattened cremaster furnished with a cluster of hooks. 
The long tongue-case extends to the anal segment; it is 
detached from the apex of the wings. 
