Forest entomology . Fig. 257.—Gall of resin on. Scots pinecaitAed by Retinia LEPIDOPTERA. 271 important factor in the life-history of the insect—viz., that the galltakes two years to reach maturity. The generation is therefore a bien-nial one. The eggs are laid in May, just under the whorl of buds,which are bursting, or about to burst, into the growing shoots. Thecaterpillar bores into the pith, and this being the most active period inthe life of the plant, causes the growth of a hollow gall resinous mass,about the size of a pea, and in this abode the larva passes the the
Forest entomology . Fig. 257.—Gall of resin on. Scots pinecaitAed by Retinia LEPIDOPTERA. 271 important factor in the life-history of the insect—viz., that the galltakes two years to reach maturity. The generation is therefore a bien-nial one. The eggs are laid in May, just under the whorl of buds,which are bursting, or about to burst, into the growing shoots. Thecaterpillar bores into the pith, and this being the most active period inthe life of the plant, causes the growth of a hollow gall resinous mass,about the size of a pea, and in this abode the larva passes the the following spring the larvacontinues feeding, but meanwhilethe gall rapidly increases in size tothat of an average gooseberry. Asection of a gall shows that it isdivided into two chambers by a strongvertical partition : in one the larvalives and pupates, and the othercontains its excrement. The pupalperiod is very short, and the mothflies about May—the generation thus Fig_ resinella. extending over two years. It generally attacks trees from six to ten years of age, b
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