PHORODESMA SMARAGDARIA. 61 
when the Artemisia is again appearing above the 
ground, they commence feeding, soon after which they 
moult and again cover themselves with pieces of the 
food-plant, which, being now green and fresh, give 
them a healthy appearance. About the middle of 
June they are full-grown, when they rest for a day or 
two, and then spin a loose network.cocoon; this they 
form by drawing together, with silken threads, the 
pieces of the Artemisia that are thickly adhering to 
their bodies, into an oval-shaped covering attached to 
the stem of the food-plant, and in it they change to a 
ereyish pupa, with the striped wing-cases showing very 
distinctly. 
The larva, when full-fed,is about an inch and a 
quarter long, of a dirty greyish colour, with darker 
lines along the body, the skin very rough, and the head 
and legs brown; but, owing to its being covered so 
entirely with the dead and brown portions of the food- 
plant, it is extremely difficult to make out the exact 
markings. It sometimes feeds at dusk, but more fre- 
quently during the morning sunshine, and at times, 
when the sun is hot, it eats most voraciously, appearing 
in a very excited state during the whole time the sun 
is shining uponit. This necessity for sunshine consti- 
tutes one of the many difficulties the collector has to 
contend with in rearing these larve, for the sun is, of 
course, a great obstacle to keeping the food fresh. 
The only way to keep the food comparatively fresh is 
to dig up the Artemisia with a large clod of earth, so 
as not to disturb the roots, and even then it rarely 
keeps longer thana week. ‘To be successful, therefore, 
with these larve, a great deal of trouble must be 
undergone. | 
The perfect insects appear about the middle of July, 
generally durmg the early morning, and remain 
motionless the whole of the first day, and I believe 
until daybreak of the next, for I have looked at them 
as late as twelve o’clock at night, and found them still 
motionless ; but, on again looking at them about seven 
