Galls caused by the larvce of Adelges abietis Linn. 



on 



the twigs of Abies excelsa De C. 



PLATE 34. 

 Synonymy of Insect. 



Clurmes abietis Linn., Fab., Schr., Kalt., Pass., Kerner, 

 Koch, Ormerod, Ratz., Leuchart. 



Adelges gallaruin abietis Haliday. 

 „ abietis Walk. 



Sacchipliantes abietis " Ruricola." 

 Habitat of the Spruce-fir.— Indigenous in the Scottish 



highlands. Planted all over Britain in parks, enclosures, 



private grounds, and nursery gardens. 

 The Gall is formed by the accumulation of sap around 



punctures made by the queen aphis at the axils of the 



young leaves, causing their bases to thicken. 

 Position. — At or near the end of a twig. 

 Manner of Growth.— The larval chambers are gregarious, 



imbricated, and sessile. 

 Colour. — At first pale green, darker later, ultimately chocolate- 

 brown. 

 Average Dimensions of a Mature Specimen. 



.Length, 40 mm. ; breadth, 16 mm. ; girth, 36 mm. 

 May be sought during the months of April, May, June, Jul>-. 

 The Growth is complete by the end of June. 

 The Typical Condition of the gall is plurilocular. Usual 



number of cells, 25. 

 ECDYSIS takes place in the gall. The imagines emerge during 



June. 



The popular name of pine-apple gall is very appropriate. 

 Before the scales separate to allow the pupa; to emerge, it 

 bears a very close resemblance to a pine-apple. In their dried 

 condition they may be observed on Christmas-trees used at 

 children's parties. 



The gall is also figured by Miss Ormerod, " Injurious 

 Insects," 1890, p. 267; Buckton, "British Aphides," vol. iv., 

 plate 116; "The Royal Natural History," sect, xi., p. 199; 

 A. Kerner, " Nat. Hist, of Plants," vol. ii., p. 534. 



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