132 



ELEMENTARY ENTOMOLOGY 



FIG. 183. The hemispherical scale 

 (Lecanium hemisphaericiim Targ.) 



a, scales on olive (natural size); l>, three 

 female scales (considerably enlarged); c, 

 female scale lifted from leaf, showing mass 

 of eggs (enlarged). (After Marlatt, United 

 States Department of Agriculture) 



of the genus Lecanittm and their 

 near relatives, and are known as 

 Lecaniums. They are usually of 

 a brownish color, quite strongly 

 convex (often ridged), and are 

 soft and easily crushed, hence 

 the name. The upper surface 

 of the female gradually hardens, 

 and upon ma- 

 turity she dies 

 and the old skin 

 forms the scale 

 which covers the 

 eggs laid be- 

 neath it. The 



Lecaniums occur upon various greenhouse plants 

 such as crotons, upon the peach and plum, 

 and upon citrous fruits. The 

 cottony maple scale is a 

 species common on maple 

 shade trees and gives off 

 a mass of cottony wax in 

 which the eggs are laid. 



The armored scales are 

 much smaller, flat, circular, FIG. 184. The cot- 

 or elongate in outline, and tony maple scale 

 include our most common (Enlarged) 

 species. Upon hatching, the 

 young scale insect crawls about for an hour or 

 two and then settles down, inserts its beak in 

 the leaf or bark, and henceforth the females 

 remain in the same place. Soon waxy fila- 

 ments commence to exude from the body, 

 which mat down into a small scale covering 

 the insect. When the skin is molted, it is 

 added to the center or one end of the scale, 



shell scale on poplar twig which is gradually enlarged and assumes a 

 (Photograph by Weed) characteristic shape. With the first molts the 



FIG. 185. The oyster- 



