Forest entomology . b-costal cellule large, always present; the othercellules badly defined or absent; submarginal nervure absent; abdo-men compressed, ovipositor originating close to the base of theabdomen, the borer usually semi-spiral, and with parts free; larvaeapterous, never spinning a cocoon ; eggs stalked ; antenna? in 9 stouterthan $ ; legs, claws simple in Cynips, cleft in some species of Andri-cus and Neuroterus. Chalcidida?.2—Wings having a stigma; no radial or cubitalcellules; antenna? elbowed ; prothorax not reaching to insertion ofwings. The details of a wing of Cynips, fig. 129
Forest entomology . b-costal cellule large, always present; the othercellules badly defined or absent; submarginal nervure absent; abdo-men compressed, ovipositor originating close to the base of theabdomen, the borer usually semi-spiral, and with parts free; larvaeapterous, never spinning a cocoon ; eggs stalked ; antenna? in 9 stouterthan $ ; legs, claws simple in Cynips, cleft in some species of Andri-cus and Neuroterus. Chalcidida?.2—Wings having a stigma; no radial or cubitalcellules; antenna? elbowed ; prothorax not reaching to insertion ofwings. The details of a wing of Cynips, fig. 129, /, should be carefullystudied, as the wings of the genuine oak-gall fly differ very muchfrom the various species of parasitic flies which are associated withthe Cynipida?. 1 Monograph of the British Phytophagous Hymenoptera, vol. iii. pp. 142,147. Ray Society. 2 This family contains many of the parasites found in oak galls, therefore it ismost important to recognise the contrasting points. 140 FOREST Adler 1 arranges the species in the four following groups—Adz. :I. JNTeuroterus. III. Dryophanta. IT. Aphilothrix. IV. Biorhiza. In attempting to give some detailed account of the various speciesof oak galls whereby the galls themselves may be recognised in theforest and the insects verified after hatching in confinement, it isobvious there are several ways open for adoption. We might follow a botanical method and describe the galls on buds,leaves, fruit, and roots; or we might adopt an entomological course,and describe and compare the various species as found on the respect-ive parts of the tree. But we shall adhereto the arrangement of Adler, because we maythen follow the commonest species and havea direct bearing on a most important biologicallaw—viz., the alternation of , take 1. Neuroterus lenticularis, (Oak-spangle Gall). This gall is very common throughout thecountry from July to September. The gallsare scattered promiscuously on
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