ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 



27 



Fig. 20. — Scurfy scale: an infestation on an elm twig. The scales are 

 gray and somewhat pear shaped. The overwintering eggs under the shells 

 are purplish. The hole made in one scale by an emerging parasite is indi- 

 cated by an arrow. 



Fig. 21. — Putnam scale: an infestation on an elm twig. The covering 

 or shell of the female scale is almost circular and about one-sixteenth inch 

 in diameter; that of the male is oblong. Near the center of each shell is a 

 brick-red nipple that contrasts with the dark gray or black remainder of 

 the shell. The scale insect beneath the shell is yellow. 



