ENGLISH: ILLINOIS TREES. THEIR INSECT ENEMIES 65 



buds and nodes of spruce. The overwintering female fills her 

 shell, about one-eighth inch in diameter, with purple eggs in 

 June. In central Illinois, the eggs hatch about the first of July. 

 The flat, purple crawlers move away from their mother to settle 

 in a new place. 



Control Measure 3 (end of circular) July 10-15. 



Spruce Budworm, Choristoneura fumiferana (Clem.). — A 

 destructive forest pest that sometimes attacks ornamental 

 spruces, the larva of this species is a dark reddish-brown cater- 

 pillar about 1 inch long when grown. It feeds on the opening 

 buds and needles, tying them together with silk. 



The overwintering caterpillar becomes active in the spring 

 and completes development. The adults, dull gray moths, emerge 

 from the pupal case in midsummer, when the female deposits 

 masses of overlapping, greenish eggs on the needles. 



Control Measure 2 (end of circular) when caterpillars are 

 actively feeding. 



Pine Needle Scale, fig. 40. — See under Pine. Control Meas- 

 ure 12 (end of circular) in winter or Control Measure 3 in June. 



SYCAMORE 



Sycamore Lace Bug, Corythucha ciliata (Say), fig. 46. — This 

 insect is probably the most common pest of sycamore. Both 

 adults and nymphs feed on the under sides of the leaves in great 

 numbers, withdrawing so much plant juice and chlorophyll that 

 the foliage becomes pale and dry. The leaves become dirty with 

 excrement. Both male and female are pretty insects; each is 

 about one-eighth inch long and has a black body and almost 

 transparent, lacelike wings held flat when at rest. By contrast, 

 the black, spiny nymph is ugly. 



The overwintering female becomes active in early spring 

 and deposits eggs on the under sides of new leaves. The eggs 

 hatch in a couple of weeks, and each nymph molts five times be- 

 fore becoming an adult, 30 to 40 days later. 



Control Measure 3 (end of circular) when the nymphs ap- 

 pear, usually in late May. 



Bagworm, fig. 2. — This, the most common leaf eater on syca- 

 more, is discussed under Arborvitae. Control Measure 1, 3, 11, or 

 21 (end of circular) as soon as the eggs hatch. Sprays applied 

 in late summer after the larvae stop feeding, or during the win- 



