160 THE INSECT WORLD. 
and left only its hinder part within. It moved its head forwards 
as far as was necessary to enable it to seize a particle of earth. 
Fig. 120.—Cucullia verbasci. 
As soon as it had got its load, it re-entered the interior of the 
cocoon. It deposited the grain of earth, and came out again 1m- 
mediately, as it did at first, to pick up another grain, which it 
carried likewise into the interior of the cocoon. This operation 
it continued for more than an hour. 
. . The provision of materials 
being got together, the caterpillar 
now devoted its whole attention to 
working them up. It began by 
spinning over one part of the edges 
of the opening. After having put 
over this a small band of very loose 
web, the caterpillar’s head left the opening, the insect went right 
back again into its cocoon, and the head returned to the opening 
loaded with a little grain of earth, which it entangled in the silky 
threads. It then entangled in them two or three, or a greater 
number of grains, according to the quantity of threads it had 
spun. It bound them into these with other threads, after 
which it drew threads over the edges of another part. By 
thus going round the whole rim of the opening, and by carrying 
and fixing the grains of earth in the threads which were the last 
stretched over the opening, it rendered its diameter smaller and 
smaller.” 
It was by working with its head that our mason gave to the 
new wall of its cocoon the necessary curvature. It was interest- 
ing to know how, as it could no longer put out its head, it could 
stop up the orifice. 
Fig. 121.—Cocoon of the Cucullia verbasci. 

