New York Agricultural Experiment Station. 353 



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 earth rounded at both ends 

 and about 7 mm. long and half as broad. (Plate XXVII, Fig. -i, 

 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 larvae 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. 

 23 



