CHERMES HIMALAYENS1S ON THE SPRUCE AND SILVER FIR. 123 



EXPLANATION OF THE PLATES. 



Plate 20. 



Fig. 1. Spruce branches showing three young pink and yellow coloured galls containing larvae of 

 Chermes Mmalaymsis. The dark-coloured gall with the gaping chambers on its surface is a 

 previous year's gall. 



2. Section across a partially grown gall on the Spruce, plucked from the tree on May 30th. 



3. Young larva taken on May 30th from a chamber in the gall portrayed in fig. 2 ( x 15). 



4. Larva about three-fourths grown. The first commencement or bulging of the wing-protuber- 



ances is seen on either side of the thorax ( x 15). 



Plate 21. 



Fig. 1. Mature galls of Chermes himalayensis on Spruce branches. The gall-chambers are just opening 

 to allow of the emergence of the fully grown larvae. July 15th, 1909. 



2. Full-grown larva on emergence from the Spruce gall. The wing-protuberances are seen on the 



lateral edges of the body ( x 15). 



3. Section across a mature gall showing the partitions and larva? in them ( x about 3). 



4. Portion of a gall showing the chambers opened by the shrinkage in drying and consequent gaping 



of the lids. The green tips of the needles which project from the centre of the lid are well 

 seen. ( X about 2.) 



5. Winged insect (Alatje) shortly after emergence from the last larval skin, showing the still 



unrolled brightly coloured wings. 



6. Winged insect (Alat^e) with wings fully unrolled and functional, from half an hour to an 



hour after emergence of larva from gall. 



7. Winged insect (Alat^e) fully developed, about three hours after emergence of larva from gall. 



The cottony material has commenced to develop on the head, thorax, and abdomen of the fly. 



Plate 22. 



Fig. 1. Young spring shoot of the Silver Fir, showing on the needles dead and living apterous females 

 with egg-masses covered over by the white cottony material. May 24th. 



2. Full-grown apterous female on a Silver Fir needle just before the development ot the 



cottony material which precedes egg-laying. May 24th. 



3. Full-grown apterous female from the spring eggs commencing to secrete the cottony material 



and to lay the first eggs. May 25th. 



4. Full-grown apterous female towards the end of the egg-laying period. May 26th. 



5. Egg-mass with cottony material removed to show method of deposition of eggs on the needle. 

 May 26th. 



6. Full-grown larva of the winged female from the spring eggs just before moulting its last 

 larval skin. May 24th. 



7. Winged female from the spring eggs showing the cottony masses beginning to appear on 

 head, thorax, and abdomen. May 25th. 



8. Young, newly hatched larva, from apterous female of the first generation of the year. 



N.B. — All the above figures were drawn from living insects in situ on Silver Fir needles at 

 Kalatope, Chamba, N.W. Himalaya, by M. E. Stebbing, mostly enlarged. 



SECOND SERIES. — ZOOLOGY, VOL. XI. IS 



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