F-500805 
FIGURE 146-——Harva) vot “the 
boxelder twig borer, Protec- 
teras willingana, in a box- 
elder stem. 
Young larvae feed singly in opening buds in the spring or on 
tender terminal needles which they web together. Some pupae are 
found on the foliage of the trees, but the majority occur immedi- 
ately below the ground surface. Winter is passed in the egg stage, 
and there is one generation per year. Zeiraphera diniana Gn. 
occurs all the way across southern Canada and possibly in the 
northern tier of States. It appears to prefer larch and spruce, but 
several other conifers are also infested. Z. fortunana (Kft.) 
occurs commonly from coast to coast in southern Canada. Infes- 
370 
