INSECT PESTS OF OHIO SHADE AND FOREST TREES 299 



rather severely attacked. More extensive outbreaks have been 

 recorded from other states. In Massachusetts and some of the 

 other New England States it is considered a serious pest of street 

 trees. 



Food plants. — While maple without doubt is the chief food 

 plant, the insect has been reported upon hornbeam, lime and horse 

 chestnut. 



Distribution. — The northeastern quarter of the United States 

 constitutes the area over which the maple Phenacoccus is most 

 frequently found. 



Natural enemies. — The following natural enemies have been 

 recorded for this scale: Lady-beetles, Hyperaspis signata Oliv., 

 Chilocorus bivulnerus Muls. and Anatis ocellata Oliv. ; Syrphid fly, 

 Baccha fascipennis Wied. ; Chalcid, Rhopus coccois Smith and 

 Chrysopa ,sp. 



Control. — Miscible oil at the rate of 1 gallon to 15 of water 

 applied in the spring before the buds break is the most generally 

 approved control measure. Whale-oil soap is reported as yielding 

 favorable results, as is also kerosene emulsion. Whatever the ma- 

 terial used, it should be applied with particular thoroughness to the 

 trunk and rougher branches of the host to have it penetrate to the 

 secreted, hibernating insects, and the work should be done before 

 the foliage starts in the spring. 



THE MAPLE TERRAPIN SCALE 



(Lecanium nigrofasciatum Perg.) 



Description. — The maple terrapin scale, or black-banded scale 

 as it is sometimes called, is sharply hemispherical in form when full 

 grown and varies in length from one-eighth to one-sixth of an inch. 

 It is slightly narrower than long. The general color is reddish- 

 brown with varying degrees of black banding or mottling. Some- 

 times an individual will be entirely red or black. The usual mottled 

 appearance and characteristic form so closely remind one of the 

 land terrapins in miniature that the insect is known by some as the 

 terrapin scale. Distinct ridges radiate to the outer border from a 

 smooth, brown, central area, increasing in distinctness as the border 

 is approached. One of the most distinctive characteristics, how- 

 ever, is a peculiar, nauseating odor released when the fresh speci- 

 mens are crushed. The males are fragile, winged creatures which 

 are rarely observed unless bred out in confinement. The eggs are 

 pale yellow and are deposited under the shell-Uke scale. (See Plate 

 L, Fig. 3.) 



