Natural history of insects : comprising their architecture, transformations, senses, food, habits--collection, preservation and arrangement . ed growth of the plant, caused (it might be) bythe puncture of an insect, but not for the purpose ofa nidus or habitation.* Another sort of excrescence is not uncommon onthe terminal shoots of the hawthorn. This is ingeneral irregularly oblong, and the bark which coversit is of an iron colour, similar to the scoriae of a black-smiths force. When dissected, we find no traces ofinsects, but a hard, ligneous, and rather porous tex-ture. It is not improbable
Natural history of insects : comprising their architecture, transformations, senses, food, habits--collection, preservation and arrangement . ed growth of the plant, caused (it might be) bythe puncture of an insect, but not for the purpose ofa nidus or habitation.* Another sort of excrescence is not uncommon onthe terminal shoots of the hawthorn. This is ingeneral irregularly oblong, and the bark which coversit is of an iron colour, similar to the scoriae of a black-smiths force. When dissected, we find no traces ofinsects, but a hard, ligneous, and rather porous tex-ture. It is not improbable that this excrescence mayoriginate in the natural growth of a shoot beingchecked by the punctures of aphides, or of thosegrubs which we have described (page 389). Many of those excrescences, however, are probablyaltogether unconnected with insects, and are simplyhypertrophic diseases, produced by too much nourish-ment, like the wens produced on animals. Instancesof this may be seen at the roots of the holyhock{Aiihea rosea) of three or four years standing; onthe stems of tlic elm and other trees, immediately =^ J. R. PSEUDO-GALLS. 399.
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Keywords: ., bookcentury1800, bookidnaturalhistoryof01bos, booksubjectinsects
