THE TEEEAPIN SCALE. 43 



them in sharp contrast with the narrow ridges of the crimps. These 

 pigmented depressions blending form the first pigment zone or mar- 

 ginal pigmentation. (Fig. 15, fpz.) By the fourteenth day the female 

 has become decidedly adult, both in shape and color. The first pig- 

 ment zone now reaches completely around the dorsum and extends 

 upward as far as the anal plates; the dorsal band has blended with 

 the reddish-brown ground color, and a second zone of pigmentation 

 has formed about the rent in the original dorsal band, thus transforming 

 it into the permanent reddish-brown stripe which is so characteristic 

 of the mature female. (Fig. 15, ads.) The second zone of pigment is 

 composed of dark-brown granules similar to those in the marginal 

 region. It surrounds the amber-colored gap in the original dorsal 

 band and extends downward and outward nearly to the marginal 

 zone, from which it is separated by an irregular unpigmented zone 

 (fig. 15, uz) which lies parallel to the edge of the dorsum at about the 

 height of the anal plates. By the twentieth day the female has 

 assumed both the characteristic shape and color of the adult, but the 

 general color is not so bright as in the case of older specimens. After 

 the twentieth day there is no change in the color pattern. The pig- 

 mentation, however, deepens and the insect continues to grow, but 

 at a decreasing rate, until it hibernates. 



The data in Table XXVII show in detail the development of the 

 female up to and including the fifteenth day after attaching to the 

 twig. A very rapid growth is also shown during this period. The 

 ground color changes from light yeUow to reddish brown; the dorsal 

 band develops and breaks and the adult pigmentation starts. 



To obtain more extended observations upon the twig-attached 

 females, 100 larvae were taken August 15, 1913, while making the 

 twigward migration, and placed upon a vigorous potted peach tree. 

 This tree was kept under orchard conditions and such of the speci- 

 mens as had accessible locations were numbered and observed from 

 time to time through a Zeiss binocular. These observations were 

 continued to the sixty-seventh day after migrating. Data from 

 these specimens are given in Table XXVIII ; they supplement Table 

 XXVII. 



