CHEEMES HIMALATENS1S ON THE SPRUCE AND SILVER EIR. 117 



blackish brown in colour, with a very long proboscis and the dorsal surface covered witli 

 white cottony bristles, the lateral edges being set with a fringe of white setas, giving the 

 insects the appearance of an Icerya scale insect in miniature (PI. 23. figs. 2, 3). 



These little grubs proceed down to the parts of the shoot or branches covered with 

 the first light thin brownish-yellow cortex, insert their proboscides down through a 

 crevice into the cambium layer and remain feeding there. PI. 23. fig. 2 shows these 

 small larvae feeding on the cortex, and fig. 3 two more highly magnified. The larvae 

 pass through the monsoon rains and, I think, the autumn and succeeding winter here, 

 and form a portion of the Colonici, or apterous females, which lay the eggs of the first 

 spring generation of the year. The other or true portion of the Colonict on the Silver 

 Fir migrate from the Spruce about the middle to third week in July. It is a point 

 which will require very considerable investigation and close experiments to decide 

 whether any of the apterous females (the true Exsules) which leave the Silver Fir 

 corkscrew " bud " and lay eggs below give rise in the following year to winged insects, 

 or Sextjpar.e. 



We have now to turn to the winged insect which emerges from the Spruce pine-apple 

 gall, or pseudo-cone, and flies to the Silver Fir. This period of emergence is about the 

 middle of July, and a large proportion of the flies from the Spruce galls would seem to 

 migrate to the Silver Fir, for I have found them plentifully on the under side of the 

 needles. 



On reaching the Silver Fir the fly selects a needle below the corkscrew " bud " and 

 comes to rest on the under side in a position usually pointing up and down or parallel 

 to the long axis of the needle, the head pointing either upwards or downwards, most 

 usually the latter. 



The fly then commences to oviposit, laying from 60 to 80 or possibly as many as 100 

 eggs. The number is far greater than that of the eggs laid by the apterous female 

 on the Silver Fir. 



The eggs are egg-shaped, dark madder or umber-brown in colour, and are deposited 

 in a heap like a squashed bunch of grapes, except that the mass is more spread out at 

 the base. The eggs when first laid are flesh-pink in colour, soon darkening. 



The abdomen of the fly shrivels up after egg-laying and the upper wings remain 

 entirely covering the egg-mass, the insect dying in situ and remaining fixed to the 

 needle on taking up her position there. 



Before egg-laying the fly develops on her head and thorax a white woolly material, 

 which projects in front of the head and down the sides a little way in a manner similar 

 to that already described for the Silver Fir fly. 



When the fly gets blown or knocked off the needle, which, owing to her fragility, must 

 soon happen, the cotton remains as a covering and protection to the eggs. 



These eggs would appear to hatch out within a few days after being deposited, and the 

 young grubs crawl down onto the shoots or branches from the needles and feed in the 

 manner already described, their long proboscides being buried in the cambium down 

 through an interstice of the bark (PI. 23. figs. 2, 3). 



17* 



