14 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 



spring construct tents in a wide variety of trees, including box- 

 elder, elms, maples, and oaks. The black, hairy caterpillars 

 hatch in March from an overwintering mass of eggs plastered 

 to a twig in a brown band or collar. Caterpillars usually select a 

 fork of a branch for the construction of a tent. They leave the 

 tent to feed during the day but return at night. After feeding 

 for 5 or 6 weeks, each caterpillar spins a cocoon on a tree trunk 

 or in some other protected place, where it pupates. The adults, 

 reddish-brown moths, emerge in early summer. This insect pro- 

 duces only one generation a year. It occurs in abundance at in- 

 tervals of about 10 years. 



Control Measure 1 or 2 (end of circular). Although this 

 pest usually is kept under control by natural enemies, sprays 

 may occasionally be needed to prevent damage to valuable shade 

 trees. 



BOXWOOD 



Boxwood Leaf Miner, Monarthropalpus buxi (Lab.). — Dam- 

 age by this insect is indicated in early summer by small blotches 

 on the leaves of boxwood. Later the blotches enlarge to blisters 

 that cause the leaves to turn brown and to drop. The small yel- 

 lowish-green maggots or larvae of this species feed on the tissue 

 in the leaf during the summer and again in the spring before the 

 orange-yellow midges develop and emerge from the pupae. The 

 female deposits eggs in May for a new generation. 



Control Measure 8 (end of circular) about May 15. 



CATALPA 



Catalpa Sphinx, Ceratomia catalpae (Bdv.), fig. 9. — A rav- 

 enous feeder consuming great quantities of catalpa foliage, the 

 caterpillar of the sphinx moth may vary in color from pale yel- 

 low with green markings to almost black. The caterpillar has 

 a black, hornlike process at its rear end. When grown, the cater- 

 pillar is about 3 inches long. 



Emerging from an overwintering pupa in the soil, the fe- 

 male of this moth mates and lays hundreds of eggs in white 

 masses on the under sides of leaves. The young caterpillars 

 feed in groups at first, but work individually later, consuming 

 entire leaves. 



