. An introduction to zoology, with directions for practical work (invertebrates). . Fig. 325.—The Wood Wasp (Sirex gigas). XXVII INSECTA: HYMENOPTERA 433 of fir trees, doing much damage. It is, however, rarely found in Britain, though common in some other parts of North Europe. Cynipidae (Gall Wasps) The Gall Wasps consist of small, dark-bodied forms with long, simple, straight antennae, and with very few "nervures" and no dark patch on the wings. There is a narrow petiole be- tween the fore and hind body. The insects themselves are not usually known to the casual observer, who will,
. An introduction to zoology, with directions for practical work (invertebrates). . Fig. 325.—The Wood Wasp (Sirex gigas). XXVII INSECTA: HYMENOPTERA 433 of fir trees, doing much damage. It is, however, rarely found in Britain, though common in some other parts of North Europe. Cynipidae (Gall Wasps) The Gall Wasps consist of small, dark-bodied forms with long, simple, straight antennae, and with very few "nervures" and no dark patch on the wings. There is a narrow petiole be- tween the fore and hind body. The insects themselves are not usually known to the casual observer, who will, however, probably recognise the galls which many of them cause on the oak and other trees, for such galls are some of the most common objects of the country-side (see Plates IV., V., and VI.). Inside these galls the insects spend the first stages of their life-history. The galls are formed by the female Gall Formation ^^^P- ^^^ '^7^ ^^^i' ^gS^ i"^ the tissues of a living plant, piercing a hole for the reception of each, by means of the long ovipositor she possesses at the end of her body. The legless grub which hatches out begins at once to feed on the soft tissue around it, and the irritation of the cells which is thus caused, results in their abnormal, rapid multiplication. The larva and the gall develop together, the former feeding on the inner tissues of the latter. ' Internal '^^^ tissues of the gall around the hollow Structure cavity in which the grub lies, frequently show of a Gall, a, considerable amount of differentiation, as in the spangle gall. When cut across (Fig. 326), this shows a layer of nutritive tissue lining the cavity in which the larva lies, and round this a layer of hard protective cells VOL. I ~ 2 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 Lulham, Rosalie Blanche Jerm
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondo, bookyear1913
