. Lichens. Lichens. 398 ECONOMIC AND TECHNICAL while Tegeocranus labyrinthicus, though usually a lichen-eating species, lives either on mosses or on lichens on w^Us. ZopP reckoned twenty-nine species of lichens, mostly the larger foliose and fruticose kinds, that were eaten by mites. Lesdain^ in his observations on mite action notes that frequently the thallus round the base of the perithecia of Verrucaria sp. was eaten clean away, leaving the perithecia solitary and extremely difficult to determine. J. A. Wheldon^ found the eggs of a species of mite, Tetranychus lapidus, attached to the fruit
. Lichens. Lichens. 398 ECONOMIC AND TECHNICAL while Tegeocranus labyrinthicus, though usually a lichen-eating species, lives either on mosses or on lichens on w^Us. ZopP reckoned twenty-nine species of lichens, mostly the larger foliose and fruticose kinds, that were eaten by mites. Lesdain^ in his observations on mite action notes that frequently the thallus round the base of the perithecia of Verrucaria sp. was eaten clean away, leaving the perithecia solitary and extremely difficult to determine. J. A. Wheldon^ found the eggs of a species of mite, Tetranychus lapidus, attached to the fruits of Verrucaria calciseda, Lecidea immersa and , calcicolous lichens of which the thallus not only burrows deep down into the limestone, but the fruits form in shallow excavated pits (Fig. 126). The. Fig. 126. >, 7^elranychus lapidus, ecA&x^^A.; i, Verrucaria calciseda \«it\i eggs in situ, sW^Ay enlarged; 3 and 4, eggs attached to lichen fruits, much magnified (after Wheldon). eggs of this stone mite are found fairly frequently on exposed limestone rocks, bare of vegetation, except for a few crustaceous lichens. "There is usually a single egg, rarely two, in each pit apparently attached to the old lichen apothecium. The eggs are very attractive objects under a lens; they measure "5 mm. in diameter, and are disc-like with a central circular depres- sion from which numerous ridges radiate to the circumference, like the spokes of a wheel. When fresh, they have a white pearly lustre, becoming chalk- white when dry and ; Wheldon's observations were made in the Carnforth and Silverdale district of West Lancashire. ^ Zopf 1907. - Lesdaih 1910. â ^ Wheldon 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 Smith, Annie Lorrain. Cambridge, At the University Press
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