CHAP. CV.

couyla'ceje. que'rcus.

1827

inch in diameter, smooth on the surface next to the leaf, but hirsute and redon the outside: they are nearly flat, the thickest portion being the centre,where the point of attachment to the leaf is placed on the inside. This stalk,or funicular attachment, as it may be called, is very short, so that the excres-cence nearly lies flat upon the leaf. (See Jig. 165 2.a.) The Rev. W. T. Bree(Card. Mag., vol. xii. p. 496.) calls them oak spangles, considering them to bethe work of an insect. They are mentioned by several authors; but Mr.West-wood cannot find that their history has been satisfactorily traced by any writerupon the economy of insects. Nees von Esenbeck observes of these oakspangles, “ Mirum tamen, gallas esse, quas etiamsi frequentissimas omnium,nemo hucusque incola sua fetus invenerit, vel quomodo oriantur cognoverit.”(Hymen. Monogr., ii. p. 266.) Reaumur has described and figured them(Mem., tom. iii. mem. 12. pi. 42. f. 8. 10.) under the names of galles enchampignon, from their resemblance to a flat mushroom. He was never,however, able to discover any appearance of an internal cavity ; but he adds, “ IIfaut pourtant qu’il y en ait dans Ie milieu de quelques unes, car M. Malpighiassure l’avoir observe.” He, however, discovered that the space between theunder side of the excrescence and the leaf was the residence of a small worm,of an oblong form and yellowish amber colour, with two small points on thefront of the head. Under some of these galls one or two only were found,but as many as a dozen under others. Fabricius, without alluding to theseworms, gives the excrescences as the galls of Cynips longipennis, or Diplolepislenticulatus of Olivier, with the observation, " Habitat in galla parva depressa,monothalama Galliae. Mus. Bose.and Coquebert has figured this species ofcynips from the Boscian cabinet with two specimens of the galls, which are,however, represented so small, and so unsatisfactorily, that it is doubtfulwhether they be identical with Reaumur’s galles en champignon. But inthe collection of Chalcididae formed by Dr. Nees von Esenbeck, abovementioned, are contained specimens of this excrescence, accompanied by aspecimen of the Eurytoma signata ; and in this author’s Monog. Hymen. Ichn.Affin., vol. ii.p. 43., is the remark : “ Observavi etiam, Septembre mense, hujusspeciei feminam, cum gallam illam orbiculatam depressam lenticularem umbo-natam basi arcte appressam rubram hirsutam, quse in pagina foliorum quercusinferiori frequens occurrit, ictu vulneraret. Non causa igitur hujus speciei,sed parasita incolae ejus, videtur.” This inhabitant, on the authority ofGeoffroy (who is, however, silent on the subject) and Fabricius, he doubt-ingly considers to be the Cynips longipennis Fab. But the real habit of thisEurytoma, as he had previously ascertained, is to deposit its eggs in the gallproduced by Cynips quercus gemmae above described. The puncturing ofthe gall by the parasitic Eurytoma is not a proof of there being any internalinhabitant; because, as we learnfrom Reaumur, one or moreworms take up their abode be-neath the excrescences ; and itmight be these which the Eury-toma endeavoured to piercewith its ovipositor Mr. West-wood has, at the end of themonth of September, disco-vered many of the minute larvaementioned by Reaumur, butnever more than a single spe-cimen under each. In Jig. 1652.b shows the insect of the na-tural size; c, d, thegalls reversed,and rather magnified, with dif-ferent-sized larvae; e, larvamagnified. It was chiefly under the larger-sized and more hairy excrescences,the margins of which were deflexed, that he discovered these larv®, which

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