in determining improvements in the mechanism of growth from the point of view 

 of the insect. 



(3) Cecidomyia Taxi of the Yew is a gall-fly (Diptera) which lays an egg in the 

 tissues of the Yew bud-apex, inducing a more typical gall-construction. Terminal buds 

 are commonly attacked, and the leaf-primordia having been all laid down in the 

 previous season are not affected in number or anatomical details. But the shoots lose 

 (i) their capacity for internodal extension, (2) the D.V. habit, while the innermost 

 crowded leaves may be etiolated and colourless. The galls thus assume the form of 

 close rosette or tassel-clusters of spirally arranged foliage-needles at the end of the 

 previous season's growth (50-70), fully formed by the end of June with the shoots of 

 the new season. Larvae perennate over the winter. 



General Literature 



BAKER AND SMITH (1910), Pines of Australia; Araucaria, p. 315. 



BEISSNER (1891), Handbuch der Nadelholzkunde. 



CHAMBERLAIN ([919), The Living Cycads. 



CLINTON BAKER (1909), Illustrations of Conifers. 



COULTER AND CHAMBERLAIN (Chicago, 1910), Morphology of Gymno sperms. Further 



Literature, p. 431. 

 ELWES AND HENRY, The Trees of Great Britain and Ireland: Vol. Ill (1908), p. 571, 



Pinus sylvestris; Vol. V (1910), p. 1001, Pinus, 52 sp. 

 ENGLER AND PRANTL (1889), Pflanzenfamilien; Coniferae. Eichler. 

 GROOM (1907), Trees and their Life Histories. 

 HUTCHINS (1919), New Zealand Forestry, Part I; Kauri, p. 42. 

 KOEHNK (1893), Dendrologie. 



LAWSON (1866), Pinetum Britannicum: Sequoia, II. 20. 



MASTERS (iSgi),Jotirn. Linn. Soc., Is XVII, p. 226 ; (1903) XXXV, p. 560. (73 sp.) 

 PENHALLOW (1907), North American Gymnosperms (Timbers). 

 PENZIG (Genoa, 1894), Pflanzen Teratologie, II, pp. 485-514. 

 SARGENT (1896), Silva of North America, Vols. X, XI, XII ; Pinus, Vol. XI. 

 SAXTON (1913), ' The Classification of Gymnosperms,' New Phytologist, XII, p. 242 ; 



Further Literature, p. 259. 



SCOTT (1909), Fossil Botany ; Pteridosperms, p. 357 ; Cordaites, p. 514. 

 SEWARD (1919), Fossil Plants, Vol. IV: Recent Coniferales, p. 106; Fossil Shoots 



and Cones, p. 245; Further Literature, p. 473. 



SHAW (1914, Cambridge, U.S.), The Genus Pinus (Monograph), 66 sp. 

 STRASBURGER (1912, Eng. Trans.), Text-look of Botany; Coniferae, p. 531. 

 VEITCH (1900), Manual of Coniferae. 

 WATKYN JONES (1912), Structure of Timbers of Common Conifers: Quart. Journ. 



Forestry. 



WIELAND (190(1), American Fossil Cycads. 

 WORSDELL (1910), Annals of Botany, XIV, p. 39, Older Theories of the Pine-cone. 



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