THE CANADIAN ENTOMOLOGIST. 



339 



longer and blacker setae, and in having the yellow, basal plates of the setae 

 replaced by relatively larger, well-defined, and very distinct blackish areas. 



We have obtained, since the flight of the adults ended, larvae with 

 the following widths of heads : 2 mm., 3^/3 mm., 3^ mm., 4^ mm., 

 4^ mm., 5 mm. The length of the smallest specimen is 19 mm., 

 the diameter 2^ mm. These measurements are taken from alcoholic 

 specimens. 



We are breeding the larvae in the greenhouse in the entire willow 

 roots and in pieces of the roots, and hope eventually to be certain of the 

 length of the larval life. At present, allowing for the varying size of pupae 



Fig. 11. — Sthenopis thule. 



