CHAP. CV. 



6'ORYLAVEiE. QUE'RCUS. 



1827 



inch in diameter, smooth on the surface next to the leaf, but hirsute and red 

 on 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 fig. 1652. a.) The Rev. W. T. Bree 

 (CrVm/. Jfftg., vol. xii. p. 496.) calls them oak spangles, considering them to be 

 the 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 writer 

 upon the economy of insects. Nees von Esenbeck observes of these oak 

 spangles, " Mirum tamen, gallas esse, quas etiamsi frequentissimas omnium, 

 nemo hucusque incola sua faetas invenerit, vel quomodo oriantur cognoverit." 

 (Hymen. Monogr., ii. p. 266.) Reaumur has described and figured them 

 (Mem., torn. iii. mem. 12. pi. 42. f. 8. 10.) under the names of galles en 

 champignon, from their resemblance to a flat mushroom. He was never, 

 however, able to discover any appearance of an internal cavity ; but he adds, " II 

 faut pourtant qu'il y en ait dans le milieu de quelques unes, car M. Malpighi 

 assure 1'avoir observe." He, however, discovered that the space between the 

 under 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 the 

 front 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 these 

 worms, gives the excrescences as the galls of Cynips longipennis, or Diplolepis 

 lenticulatus of Olivier, with the observation, " Habitat in galla parva depressa, 

 monothalama Gallias. Mus. Bosc. ;" and Coquebert has figured this species of 

 cynips from the Boscian cabinet with two specimens of the galls, which are, 

 however, represented so small, and so unsatisfactorily, that it is doubtful 

 whether they be identical with Reaumur's galles en champignon. But in 

 the collection of C'halcldidas formed by Dr. Nees von Esenbeck, above 

 mentioned, are contained specimens of this excrescence, accompanied by a 

 specimen of the Eurytoma signata ; and in this author's Monog. Hymen. Ichn. 

 Affin., vol. ii.p. 43., is the remark : " Observavi etiam, Septembre mense, hujus 

 specie! feminam, cum gallam illam orbiculatam depressam lenticularem umbo- 

 natam basi arete appressam rubram hirsutam, quas in pagina foliorum quercus 

 inferior! frequens occurrit, ictu vulneraret. Non causa igitur hujus speciei, 

 sed parasita incolae ejus, videtur." This inhabitant, on the authority of 

 Geoffrey (who is, however, silent on the subject) and Fabricius, he doubt- 

 ingly considers to be the Cynips longipennis Fab. But the real habit of this 

 Eurytoma, as he had previously ascertained, is to deposit its eggs in the gall 

 produced by Cynips quercus gemmae above described. The puncturing of 

 the gall by the parasitic Eurytoma is not a proof of there being any internal 

 inhabitant; because, as we learn 

 from Reaumur, one or more 

 worms take up their abode be- 

 neath the excrescences ; and it 

 might be these which the Eury- 

 toma endeavoured to pierce 

 with its ovipositor Mr. West- 

 wood has, at the end of the 

 month of September, disco- 

 vered many of the minute larvae 

 mentioned by Reaumur, but 

 never more than a single spe- 

 cimen under each. In fig. 1652. 

 b shows the insect of the na- 

 tural size; c,rf,thegalls reversed, 

 and rather magnified, with dif- 

 ferent-sized larvae ; c t larva 

 magnified. It was chiefly under the larger-sized and more hairy excrescences, 

 the margins of which were deflexed, that he discovered these larvae, which 



6c 3 



1652 



