New Yorx AcricviruraL Exprriment Sration. 858 
the base of the bushes before going into the ground. Also later 
in the season more of the cocoons were found about 2 feet from 
the bushes than close to the base. The cocoons are formed from 
2 to 3 inches below the surface of the ground. 
The cocoon.— The cocoons are not easily recognized owing to 
their close resemblance to the surrounding earth. They resemble 
an oblong, nearly cylindrical pellet of carth rounded at both ends 
and about 7 mm. long and half as broad. (Plate XX VII, Fig. 4, 
natural size, Fig. 5 enlarged.) One cocoon is broken at one end, 
‘showing the head of the imprisoned larva. The cocoons are 
largely composed of a dark-brown, mucilaginous substance to 
which the surrounding particles of earth adhere and which upon 
hardening becomes brittle and shining. It is insoluble in water, 
weak acid or alkali. Running through this substance and some- 
times within the cell are occasional strands of coarse, brown silk. 
Thus it appears that the larva first spins a coarse network of 
silk to partially support the sticky mucilage in process of harden- 
ing. Although none of the larve under observation were noticed 
to molt or otherwise shed their spines before entering the ground, 
no trace of the spines could be found in the cocoons. 
Within this tight, almost waterproof cocoon, the transforma- 
tion to the pupa state slowly takes place. At first there is but 
little change in the appearance of the imprisoned larva, except 
that it is not covered with spines as formerly, but within 2 or 
3 days has shrunken somewhat and become rigid and motion- 
less. It remains in this condition all summer and all the follow- 
ing winter, slowly assuming the shape of the pupa. ‘The trans- 
formation is finally completed during the latter part of March or 
in April. Specimens kept in moist earth in the laboratory pu- 
pated early in April. 
The pupa.— The true pupa stage lasts but a few days. The 
pupa is pale green in color, becoming darker a few days before 
the mature insect emerges. 
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