. Annual report - Entomological Society of Ontario. Entomological Society of Ontario; Insect pests; Insects. ENTOMOLOGICAL SOCIETY 65 the affected tissues, however, are apparently secondary. A virus disease is also possible but so far the evidence is against this. The injection of some toxin, enzyme, or stimulating substance seems more probable. The Adelgids are a gall-forming group, although their gall-forming proclivities have so far been observed only on the primary hosts, of the genus Picea. It seems probable that "gout" is the result of a stimulation similar to that which produc
. Annual report - Entomological Society of Ontario. Entomological Society of Ontario; Insect pests; Insects. ENTOMOLOGICAL SOCIETY 65 the affected tissues, however, are apparently secondary. A virus disease is also possible but so far the evidence is against this. The injection of some toxin, enzyme, or stimulating substance seems more probable. The Adelgids are a gall-forming group, although their gall-forming proclivities have so far been observed only on the primary hosts, of the genus Picea. It seems probable that "gout" is the result of a stimulation similar to that which produces the galls on spruce. The solution of the problem might throw some light on the whole question of the chemical or physical forces con- trolling the activity of the cambium in the formation of compression wood. Literature Cited (1) Annand, P. N., 1928. A Contribution Toward a Monograph of the Adelginae of North America, p. 74. Stanford Univ. Press. (2) Balch, R. E-, 1931. Forest Insects in Nova Scotia. Forestry Chron- icle, v. 7., p. 63, June. (3) Chrystal, R. N., 1926. The Silver Fir Chermes. For. Comm. Bull. 7. London. (4) Felt, E. P., 1910. Jour. Ec. Ent., Ill, 342-343. (5) Schneider-Orelli, Schaeffer und Wiesmann, 1929. "Untersuchungen uber die Weisstannenlans Dreyfusia nusslini C. B. in der ; Mitteilungen der Schweizerischen Centralanstalt fur das forstliche Versuchswesen XV. Fig. 1—Stand being killed by "stem attack". The two trees on extreme right and left already killed, other four Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Entomological Society of Ontario; Ontario. Department of Agriculture. Toronto, The Society
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