178 



FRUIT INSECTS 



of the scales. The males are sometimes quite numerous on 

 certain branches. 



The details of the development and life history of this scale 

 are very similar to those of the oyster-shell scale. There is 

 evidently a single brood annually in its northern range, but two 



broods are recorded 

 in Illinois, Ohio, 

 Pennsylvania, Del- 

 aware and south- 

 ward. In 1895 we 

 reared in New York 

 two generations of 

 1 he scurfy scale and 

 ( )ne generation only 

 of the oyster-shell 

 scale from eggs 

 which hatched May 

 13 on trees in an in- 

 sectary, and found 

 corroborative evi- 

 dence on trees in 

 the field, but this 

 was doubtless an exceptional season. The minute, purplish 

 young which hatched May 13, molted first early in June, and 

 the females the second time about a week later. By the middle 

 of June the males had emerged and by July 9 many of the eggs 

 were laid, and these hatched in about ten days. On August 22, 

 a mature male and female in the same stage as those on the tree 

 in the insect ary, were seen in the field, and eggs were laid during 

 the first three weeks in September. Owing to the purplish 

 bodies of the young and half-grown scurfy scales and the 

 thinness of the scale, they are not nearly so conspicuous on the 

 bark as the oyster-shell species. The number of purplish-red 

 eggs laid by the females varies from 10 to 85, averaging about 



Fig. 176. — Apple infest ed with scurfy scale. 



