British oak galls / by Edward T. Connold.

  • Edward Thomas Connold
Date:
1908
Catalogue details

Licence: In copyright

Credit: British oak galls / by Edward T. Connold. Source: Wellcome Collection.

    87/266 page 63
    small trees, but more generally on tlie lower tlian the upper brandies ; very rarely on scrub-oaks of less than three years’ growth. Andricus inflator, Hartig. (Plate XI.) Andricus inflator, Adler, Miiller, Mayr, Mosley, Fitch., Cameron; Cynips inflator, Thoms. English name of gall.—“The Twig Grail.” Position of gall.—At the extremity of twig or shoot. Manner of growth.—Single, glabrous, sessile, glossy. Colours.—G-reen, dark green, brown, dark brown. Average dimensions of a mature specimen. — Height, 15 mm.: breadth, 10 mm.; girth, 30 mm. May be sought during any month of the year. Growth is complete by the end of September. The typical condition of the gall is bilocular, but unilarval. The larva pupates in the gall. The imago emerges during' June to August. Parasites, Nos. 21, 56, 83, 87, 154. Inquiline, No. 110. Alternate agamic generation : Aphilothrix globuJi, Hartig. The gall results from the gall-wasp laying its egg in the axis of the terminal bud. When the bud develops in the spring the apical portion remains whitish for a long while. In all stages of development the gall is easily recognisable. In some districts this gall is exceedingly abundant, and many oak bushes have a very great number of the galls on the twigs; but there is not always a pro- portionate abundance of the alternate generation in the succeeding autumn. The egg is laid in the axis of a bud during September or October by Aphilothrix globuli. Xo gall-growth takes place until the following spring, when the larva hatches. Rapid swelling of the tissues then begins, resulting in an enormously thickened and stunted shoot. During the summer leaves and occasionally short twigs grow from the exterior of the gall. In
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