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VI. On the Life-History 0/ Chermes himalayensis, Steb., on the Spruce (Picea Morinda) 

 and Silver Fir (Abies Webbiana). By E. P. Stebbing, F.L.S., F.Z.S., F.B.G.S., 

 F.E.S., Imperial Forest Zoologist to the Government of India. 



(Plates 20-23.) 



Read 17th March, 1910. 



I. Chermes himalayensis, Steb., on the Spruce {Picea Morinda) and 

 Silver Fir (Abies Webbiana). 



References : Chermes abietis, Buck. Ind. Mus. Not. iii. pp. 5, 54. 



Chermes abietis-picete , Steb. Jour. As. Soc. Bengal, lxxii. pt. ii. pp. 37, 229. 



General Bemarks. 



IN April 1892 some galls found on Spruce trees (Picea Morinda) near Chakrata, 

 in tbe North-West Himalaya, were sent to the Indian Museum, Calcutta, by Mr. J. S. 

 Gamble, F.R.S., the Director of the Imperial Forest Scbool, Dehra Dun. The galls 

 were found to contain insects, but these latter were too immature at this period to 

 render identification possible. In July 1893 further specimens were sent from the same 

 locality by Mr. A. Smythies, Deputy Director of the School and late Conservator of 

 Forests, Central Provinces. Mr. Smythies procured some mature flies from the galls, 

 which were identified by the late Mr. Buckton as Chermes abietis, Kalt., the well-known 

 Spruce gall Aphis of Europe *. 



In May 1901 and June and July 1902 the writer had an opportunity of visiting the 

 forest from which the above-mentioned specimens were sent, and neighbouring areas, 

 and made a study of this Chermes. As is well known, Chermes viridis, Batz., lives in 

 Europe upon the Spruce and Larch, series of agamic generations alternating between 

 these two trees, a sexual generation occurring but once a year in the autumn and then 

 always upon the Spruce, whilst another species, Chermes abietis, Kalt., fives only on 

 the Spruce. 



In 'Injurious Insects' (1899), in quoting the discovery! of Chermes abietis in the 

 North- West Himalaya, a locality I had not at the time visited, I pointed out that it 

 would be interesting to know whether the Spruce grew pure in that locality, and if so 

 whether the insect existed on that tree alone. 



My investigations during 1901 and 1902 led me to the discovery that the Chermes 

 lived in a somewhat similar manner in the Himalaya to its European confrere, 

 C. abietis, but that in the absence of the Larch the second host plant was the Silver Fir 



* Ind. Mus. Notes, vol. iii. no. 5, p. 54. 

 t Injur. Ins. Ind. For. p. 23 (1899). 

 SECOND SERIES. — ZOOLOGY, VOL. XI. 15 



