272 NEW YORK STATE MUSEUM 



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 exuvise (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, slightly 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 hatch- 

 ing of the eggs in late June and early J uly, is more conspicuous than 

 any other found in this part of the United States. It is observed 

 more frequently upon the soft maple, Acer dasycarpwn, than else- 

 where, but it is often found infesting grapevines where it is known 

 as the grapevine bark-louse. It was described forty years ago as 

 Coccus innumerabilis — (nowinoluded in the genus Pulvinaria) — 

 the specific name applicable both to the myriads in which it appears 

 in some localities and to the immense number of eggs produced by 

 the female : often a thousand or more can be counted from under- 

 neath a single scale. Fig. 1 of Plate III 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 sub-oval form, bearing upon the nar- 

 rower 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 

 distance on its middle : on the front is a medial ridge for about one- 

 fQurth or one-third its length : it usually shows five transverse 

 wrinkles or folds and about the same number of raised lines run- 

 ning outwardly on each side to the hinder margin. A common 

 appearance of the adult scale is shown at b of Fig. 3 of Plate III, 

 and at b and c, immature forms in Fig. 4. 



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

 Pulvinaria, is a secretion thrown out by the insect for the protec- 

 tion of its eggs, and also of the young insects for a short time after 

 their hatching. 



