122 MR. B. P. ST EBBING ON THE LIPE-HISTOET OF 



An illustration such as the above detailed one carried out by Mr. Burdon will appeal 

 most forcibly to tbe forester, for be can appreciate at a glance the tremendous damage 

 beinc done to bis young growth if much of this sort of thing is taking place amongst it. 



I have little doubt that were experiments of this nature carried on over a period of 

 years in, for instance, a Spruce ai'ea in Jaunsar, where the Chermes is abundant, results 

 of a similar nature to those arrived at by Mr. Burdon at Cambridge would be recorded 

 from the Himalaya. And the damage done by our Himalayan insect is much more 

 severe, since every infested bud, i. e. shoot, means the total disappearance of that shoot. 



On the Silver Fir, again, the growth of young trees is seriously impeded owing to the 

 peculiar method of feeding of the later generations, or second generation, of the Colonici 

 (the Exsules and Sexupar^e). This results, as we have seen, in a contortion and dwarfing 

 of tbe upper parts of the new shoots attacked by the insect, the needles on the upper 

 half twisting round one another tightly to form a loose kind of gall-like structure, the 

 needles of which subsequently wither, dry, and open to allow of the exit of the insects. 

 This upper part with its portion of the stem turns yellow and drops of. 



An experiment of a similar nature to Mr. Burdon's with the Spruce would be of high 

 interest to ascertain the damage done to young trees by this curling up of the ends of 

 the new growth of the year. 



This is not the only damage done to the new year's shoot, as many of the lower needles 

 of the year are attacked by Chermes grubs either before they have moved into the 

 corkscrew or by those which remain outside. Each one of these at the point where 

 it pierces the tissue of the leaf and feeds causes tbe chlorophyll to be destroyed, 

 and tbe needle becomes bent at the point, the upper portion often drying up and 

 dropping. 



I have seen (it is a common sight in parts of the hills) young trees with 90 

 per cent, of the new shoots corkscrewed up in the above-mentioned manner, whilst the 

 branches below and the main stem showed numerous patches of the cottony egg-masses. 

 The eggs in these cottony masses we have seen hatch out into the young grubs shown in 

 PI. 23. figs. 2, 3, and these would appear to pass the rest of the year and the winter 

 sucking the sap from the young cortex-covered branches through their long proboscides. 

 I have found these larvae in thousands upon the branches of young trees in late July, 

 and the drain they must exert upon the young trees cannot but be otherwise than most 

 prejudicial to their growth. 



Of course the habit of growth of the Spruce and Silver Fir in mixture in the Himalaya 

 facilitates the increase and distribution of the pest. The insect is certainly responsible 

 to a far greater degree than we foresters in India have realized for the poor state of the 

 young growth of Spruce and Silver Fir in many parts of tbe Western Himalaya. 



In young badly-infested plantations it might be serviceable to snip off the galls from 

 the Spruce before the flies issue, since in the case of the Indian insect the whole of the 

 shoot is usually affected in their formation, and thus there is no chance of any further 

 growth being obtained from it. 



My acknowledgments are due to my friend Mr. E. B. Burdon for bis courteous 

 permission to reproduce the two text-figures on page 121. 



