204 NEW YORK STATE MUSEUM 



of its favorite food-plants. Ivy. when grown within doors, is quite sub- 

 ject to its attack, and is liable to be killed by it unless care is taken to 

 prevent the multiplication of the scale. Prof. Comstock reports having 

 studied the species on the following named plants: Acacia, magnolia, 

 oleander, maple, Yucca, plum, cherry, currant, English ivy and lemons 

 from the Mediterranean. 



The scale of the female is nearly circular, flat, whitish or light gray, 

 with the dull orange exuviae (cast skins) central or nearly so. The 

 ventral scale (as distinguished from the exuviae) is a mere film applied to 

 the bark. Diameter when full-grown, one-twelfth of an inch. The male 

 scale is snowy-white, shghtly elongated with the light yellow larval skin 

 nearly central; diameter one-half that of the male. It is distributed over 

 all the United States, and over much of Europe. 



The Maple-tree Scale-insect. 



This is one of our largest scale-insects, and, at the time of hatching of 

 the eggs in late June and early July, is more conspicuous than any other 

 found in this part of the United States. It is observed more frequently 

 upon the soft maple, Acer dasycarpum, than elsewhere, but it is often 

 found infesting grapevines, where it is known as the grapevine bark-louse. 

 It was described forty years ago as Coccus mtmmerabilis — now included 

 in the genus Pidvmaria — the specific name applicable both to the 

 myriads in which it appears in some localities and to the immense num- 

 ber of eggs produced by the female : often a thousand or more can be 

 counted from underneath a single scale. Fig. [ of Plate X illustrates the 

 scale as it appears when attention is usually drawn to it. It is then seen 

 as a white, cottony mass of from three- to nearly four-tenths of an inch 

 long, about one-half so broad, of a suboval form, bearing upon the 

 narrower end a brown scale darker at the margin, somewhat flattened 

 down or bent upward near its middle to nearly a right angle, oval, 

 broader behind, where it is notched and apparently cleft for a short dis- 

 tance on its middle; on the front is a medial ridge for about one-fourth 

 or one-third its length ; it usually shows five transverse wrinkles or folds 

 and about the same number of raised lines running outwardly on each 

 side to the hinder margin. A common appearance of the adult scale is 

 shown at b of Fig. 3 of Plate X, and at a, b, and c, immature forms in 

 Fig. 4. 



The white cotton-like mass, which is a characteristic of the genus Pul- 

 Tjinaria, is a secretion thrown out by the insect for the protection of its 

 eggs, and also of the young insects for a short time after their hatching. 



