THE COMMON BLUE 
223 
but of short duration. It flits about from flower to flower, 
and at times it may be seen rapidly gliding and fluttering over 
the herbage from one place to another ; it is always an active 
species when on the wing. 
Hibernation. P. icarus passes through hibernation .in the 
larval stage. Usually only a small number of the larvae 
from eggs laid by the first brood feed up and pupate the same 
summer ; the majority feed and grow very slowly and conse¬ 
quently remain very small. After the second moult they 
enter into hibernation at the end of September or early in 
October. They take up their winter quarters at the base 
of the plant quite close to the surface, resting on the stalks, 
moss, or other litter surrounding the stems of the plant. 
They remain in complete torpidity throughout hibernation, 
until the following March or early April, 
The common food plant of the larva is Bird's Foot Trefoil. 
The larva also feeds on Black Medoc (Mcdicago lupulina), 
Rest-harrow (Ononis spinosa), and different kinds of Clover, 
on all parts of the leaves, flowers 
and tender shoots. In captivity 
the larvae flourish on Green 
Peas and Beans ; they bore 
into the fleshy parenchyma of 
the pod to feed on the tender 
young bean. 
Egg and Egg Laying. When 
depositing its eggs, the female 
flutters from one plant to an¬ 
other, settles on a sprig of 
Lotus and lays a single egg on 
the basal upper surface of a 
leaflet, usually on one of the 
small young leaves ; she then 
flies off to another plant to re¬ 
peat the process. 
The egg is only o*6o mm. in 
diameter, and of a compressed 
circular form. The crown is 
sunken and the micropyle The Common Blue ; three males, 
deeply sunken. The upper sur- Sketched from life. 
