CHERMBS HIMALAYENSIS ON THE SPRUCE AND SILVER FIR. 113 



have found the egg-masses and wool-coverings at the beginning of May at elevations as 

 great as 9300 ft., whilst snow was still lying upon the ground. 



At times these woolly egg-masses are so numerous as to clothe the bark of the stems of 

 young trees more or less entirely from top to bottom, either encircling the stem or 

 occupying one or two sides only. Or the eggs may have been laid on the upper portion 

 of the stems of old trees and poles or on parts of the side branches. Tops, leading shoots, 

 and branches covered in this rnauner have the appearance of being infested with the 

 white filaments of a fungus {cf. PL 23. fig. 4). 



An examination of these cottony masses with a lens early in May will show that the 

 wool-like material merely serves as a protection to a blackish skin, the dried-up remains 

 of the over-wintering mother. This skin partially covers the bunch of yellowish-brown 

 glossy elliptical eggs. We have seen in the case of the Spruce that the eggs are merely 

 partially protected by the dried female skin, no cottony material being excreted by the 

 stem-mother (Pundatrices). The eggs, laid anywhere on the bark of the stem of the 

 Silver Pir, appear to require more protection than in the case of those laid beneath the 

 immature buds on the branches of the Spruce ; and this would seem to be the reason for 

 the development by the Colonici mothers, and, as we shall see, by the apterous females 

 of the spring generations, of the cottony mass to serve as a protection to the eggs. 



I have found the eggs in millions upon Silver Fir trees in years of bad infestation. 



In the first week of May small larvae {cf. PL 22. fig. 8) hatch out from the eggs, and 

 these at once crawl up on to the newly developed or developing needles of the tree, at this 

 period just bursting through the bud-scales, where they appear as minute black specks 

 covering the bright green tassels of needles. They insert their proboscides into the tissue 

 of the under surface of the needle and remain fixed in this position. They are never to 

 be found on the upper surface of the needle. These larvae resemble exactly the young 

 larva? to be found at this period within the newly forming pine-apple galls or pseudo- 

 cones of the Spruce. Within a few days, however, the young Aphids on the Silver Pir 

 begin to secrete on the dorsal segments a white cottony material, which is extruded in 

 bunches from certain parts of the segments and serves undoubtedly as a protection to 

 screen the grubs from the eyes of predaceous birds and insects, &c. To the naked eye 

 the young grubs appear at this period to be attacked or surrounded by the fine white 

 filaments of a fungus. 



Towards the end of the third week in May, after at least two mo ul tings (I think the 

 total number is 3) of the skin, the grubs mature, and at this j>eriod some at least lose the 

 white cottony covering and appear as the ovate brown apterous female shown in figure 2 

 in Plate 22. 



These are the Exsules, or apterous insects, which remain on the Silver Pir. 



These apterous females as soon as mature begin to develop cottony material, the first 

 filaments being secreted from segmental divisions of the head and thorax. Soon after 

 filamentous masses are extruded between the abdominal segments, and the whole insect 

 is almost entirely covered by the woolly mass. As soon as the first cottony filaments 

 have begun to make their appearance the apterous female commences egg-laying, the 

 eggs being extruded from the anal end of the body (fig. 3). These eggs are lightish 



