358 



Bulletin No. 112. 



[January, 



A conspicuous and very efficient 

 enemy is a small hemispherical lady- 

 bug {Hyperaspis binotata, Fig. 7) 

 about an eighth of an inch long, jet- 

 black, with a small dark-red spot on 

 each side of the middle. It is often 

 seen on the leaves of infested trees 

 and on plants beneath. The white 

 thick-bodied larvae of this species 

 (Fig. 7, d), which feed on the eggs 

 of the scale, may often be found 

 buried in the egg-mass or crawling 

 about on the twigs. The pupa of 

 this ladybug is formed within the 

 cottony egg-mass, and soon changes to the adult. The beetles pass 

 the winter wherever they may find shelter about the tree or on the 

 ground beneath. The larger but similarly-colored "twice-stabbed 

 ladybug" (Chilocorus bivulnerus, Fig. 8), with its black spiny 

 larva, also. destroys many maple scales. 



Fig. 7. A Ladrbug, Hyperaspis bino- 

 tata, enemy of cottony maple 'scale: "«, 

 adult; d, larva; *, c, antenna and palpus 

 of adult. Adult about J^ as long as Chi- 

 locorus bivulnerus, similarly colored; 

 larva, white. (Sanders, U.S. Department 

 of Agriculture.) 



7 IP» '9 



Fig. 8. A Ladybug-, Chilocorus bivulnerus, larva, pupa, and adult, enemy of cottony 

 maplescale. Natural size indicated at right; color black, adult with two red spots. 

 (Comstoclc, U.' S. Department of Agriculture.) 



Summary. 



1. Injuries by the cottony maple scale are commonly periodical. 

 A period of destructive abundance and following scarcity extends, 

 on an average, over eight or ten years, the disappearance- of the in- 

 sect being apparently due in the main to depredations by its insect 

 enemies. 



2. A partial exception to the foregoing statement is presented by 

 the existing outbreak in northeastern Illinois, and especially in Chi- 

 cago, where the maple scale has continued injurious for at least six 

 years, and gives no marked present evidence of a general decline in 

 numbers. 



