108 MR. E. P. STEBBING ON THE LIFE-HISTOKY OF 



"These, then, constitute the most important events which characterise the development of the galls 

 during the first stage — that is, whilst still enclosed in the bud-scales. 



" One very noticeable feature is the apparent absence of any effort on the part of the plant to resist 

 the attack, for the insect appears to have everything its own way. This is, I think, chiefly due to the 

 fact that the shoot is enclosed in the bud-scales, which exclude light and air, and thus keep the tissues 

 of the shoot in a plastic condition. . . . 



"Although my examination of the later stages is not yet complete, I have seen enough to convince 

 me that the conditions are reversed in the next stage, and a great effort is made by the shoot to 

 overcome the influence of the insect. And this effort is to some extent successful, in so far as the shoot 

 is enabled to limit the insect's sphere of influence to the area over which it has already gained sway. 

 But the effort is made too late, and always ends in the death of the galled portion of the shoot, if not 

 of the whole shoot. 



"With regard to the ultimate cause of the gall-formation, there is, I think, good reason to believe 

 that it is due to an injection by the Chermes mother. It would be out of place in this paper to give 

 the reasons for this belief in detail, but the behaviour of the chlorophyll, tannin, protoplasm, and nuclei, 

 and the gradual radiation of the influence in every direction all seem to point to an injection as the 

 cause. Further, if the insect be removed, say a week after it has commenced to suck, the abnormal 

 growth is not brought to an end. The gall continues to develop, and emerges from the bud-scales 

 just as if the insect had never been removed. The only possible explanation of this posthumous 

 growth appears to me to be, that the poison injected during that week of the iusect's life continues to 

 act on the tissues of the plant after the death of the mother." 



The pseudo-cone caused by the Himalayan insect continues to steadily increase in size 

 throughout June and the young larvse inside turn to a dark purplish-madder colour. 

 They moult their skins whilst in the chambers, at least three moults taking place, and the 

 white papery cast skins can be found in the chambers. "When nearing their full growth 

 from six to eight or at times an even greater number of larva? occupy each chamber. 



Several pseudo-cones are often to be found on the same branch (cf. PI. 20. fig. 1 and 

 PI. 21. fig. 1), and I have at times seen young trees loaded with these galls, the latter 

 having all the appearance of true fir-cones, the great number present addiug to this 

 deceptive appearance. 



In the early days of July the young larvae in the galls reach full growth and the 

 galls commence to open. It has been noted that those situated on sunny slopes and on 

 the sunny side of the tree open first. 



The gall or pseudo-cone in the process of what may be termed " ripening " changes 

 from green to orange-yellow and pale crimson ; this takes place first on one side after 

 the manner of a ripening apple and then all over, the gall often becoming bright 

 crimson for a time, finally turning, when the insects are ready to emerge, to a dull purple, 

 with the exception of a small patch or point in the centre of each of the diamond- 

 shaped covers (where the upper part of the needle would come off in the European 

 Spruce and Larch Gall), which remains bright green (PI. 21. fig. 1). 



I give the following description (with some additions and corrections) of the opening 

 of the cone and the acquisition on emergence of their wings by the full-grown larvae or 

 nymphs from my paper already alluded to as published in the •' Journal of the Asiatic 

 Society of Bengal ' : — 



The cone does not necessarily commence opening at the top : the small chambers 



