. Elements of zoology, to accompany the field and laboratory study of animals. Zoology. 58 ZOOLOGY female ichneumon are, in some cases, used to drill holes into trees occupied by insect burrows, so that her eggs can be laid therein. These parasitic species are invaluable to agriculture in keeping down injurious insects. The gall-wasps, popularly not distinguished from the strict gall-flies, are familiar to us from their works. They lay eggs. Fig. 04. -Larvii? of sa^Yfi\" on grape loaf Photo, b}' ^'. H. L. in various kinds of plants, especially in oaks and members of the rose family. An ex
. Elements of zoology, to accompany the field and laboratory study of animals. Zoology. 58 ZOOLOGY female ichneumon are, in some cases, used to drill holes into trees occupied by insect burrows, so that her eggs can be laid therein. These parasitic species are invaluable to agriculture in keeping down injurious insects. The gall-wasps, popularly not distinguished from the strict gall-flies, are familiar to us from their works. They lay eggs. Fig. 04. -Larvii? of sa^Yfi\" on grape loaf Photo, b}' ^'. H. L. in various kinds of plants, especially in oaks and members of the rose family. An excessive growth of the plant tissue, called a gall, is caused either by a poison dropped into the plant with the , or by the irritation of the developing emliryo.' The galls of gall-wasps are often more or less spherical masses which are closed, in consequence of which the confined insect must bore its way out. The galls made by the same species of insect on one kind of tree are quite similar, but if the same insect stings another species of tree a different kind of gall is produced. Also when different species of gall-wasps sting one 1 Cf. Fig. 93, p. 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 Davenport, Charles Benedict, 1866-1944; Davenport, Gertrude Anna Crotty, 1866- joint author. New York, Macmillan
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1911
