Page:Encyclopædia Britannica, Ninth Edition, v. 10.djvu/54

Rh 44 American C3/m'ps seminator, Harris, according to Mr W. F. Bassett,1 is the petiole, and its terminal tuft of woolly hairs the enormously developed pubescence of the young oak-leaf. The inoss-like covering of the “bedeguars” of the wild rose, the galls of a Cynipid, Ii’lzo«li'tes rosce, represents leaves which have been developed with scarcely any parenchynia between their ﬁbro-vascular bundles; and the “ artichoke-galls” or “ oak-strobile,” produced by Aplzilotln'i'.1c gamma’, L., which insect arrests the development of the acorn, consists of a cupule to which more or less modiﬁed leaf-scales are attached, with a peduncular, oviform, inner gall.2 Mr E. Newman held the view that many oak-galls are pseudobalani, or false acorns : “to produce an acorn has been the intention of the oak, but the gall-ﬂy has frustrated the attempt.” Their formation from buds which normally would have yielded leaves and shoots is explained by Parﬁtt as the outcome of an effort at fructiﬁcation induced by oviposition, such as has been found to result in several plants from injury by insect-agency or otherwise.3 Galls vary remarkably in size and shape according to the species of their makers. The polythalamous gall of Aphilot/u‘i.n: railicis, found on the roots of old oak-trees, may attain the size of a iiian’s ﬁst; the galls of another Cynipid, .ln(lricus occultus, Tschek,4 which occurs on the male ﬂowers of Quercus sessilz_'ﬂora, is 2 millimetres, or barely a line, in length. Many galls are brightly coloured, as, for instance, the oak-leaf hairy galls of b'pai‘hegaster tricolor, which are of a crimson hue, more or less diffused according to exposure to light. The variety of forms of galls is very great. Some are like urns or cups, others lenticular. The “kiioppern” galls of C'_2/nipspolycera, Gir., are cones having the broad, slightly convex, upper surface surrounded with a toothed ridge. Of the Ceylonese galls “ some are as symmetrical as a composite ﬂower when in bud, others smooth and spherical like a berry; some protected by long spines, others clothed with yellow wool formed of long celhilar hairs, others with regularly tufted hairs.”5 The characters of galls are constant, and as a rule exceelingly diagnostic, even when, as in the case of ten different gall-gnats of an American willow, Sal-ix lmmilis, it is difficult or impossible to tell the full-grown insects that produce them from one another. In degree of complexity of internal structure galls differ considerably. Some are monothalamous, and contain but one larva of the gall-iiiaker, whilst others are many-celled, and numerously inhabited. The largest class are the unilocular, or simple, external galls, divided by Lacaze-Duthiers into those with and those without a superﬁcial protective layer or rind, and composed of hard, or spongy, or cellular tissue. In a common gall-nut that authority distinguished seven constituent portions :— an epidermis ; a subdermic cellular tissue ; a spongy and a hard layer, composing the parenchyma proper; ‘vessels which, without forming a complete investment, underlie the pareuchyma; a hard protective layer; and lastly, Within that, an alimentary central mass inhabited by the growing larva.“ Galls are formed by insects of several orders. Among the Hymenoptera are the gall-wasps (03/n2'ps and its allies), which infect the various species of oak. They are small insects, having straight antennae, and a compressed, usually very short abdomen, with the second, or second and third segments greatly developed, and the rest imbricated, and concealing the partially coiled ovipositor. The transforma- ‘ See in Proc. Entom. Soc. of London for the year 1873, p. xvi. ” See A. Miiller, G'arden.er’.s Chronicle, 1871, pp. 1162 and 1518 ; and E. A. Fitch, Entomologist, xi. p. 129. 3 Entomologist, vi. pp. 275-8, 339-40. 4 l'rrhan(ll. cl. zoolo_r/.—bot. Gas. in Wien, xxi. p. 799. 5 Darwin, Variations of Animals and Plants under Domestz'catz'on, . . Q32. " “ lteclierches pour servir :3. l'Histoire des Galles," Ann. des Sci. Nat., xix. pp. 293 sqq. ii GALLS ' tions from the larval state are completed within the gall, ' out of which the iniago, or perfect insect, tuiniels its way,—— usually in autumn, though soiiietnnes, as has been observed of some individuals of (,‘_y1u'ps Kullcirz, after hibernation. I The phenomena of development in Cm: fps and associated genera present many features of interest. I'ot fewer than 12.000 living specimens of 0. Kollari, Gir. (C. Ii'_qni'cola,1I:irt.), from l)evons-hire galls, were examined by the late M r l"rcderick Smith,7 of the British Museum, and proved to be all females, as also were the flies obtained in two successive years from some of these by breeding on isolated I oak trees in the neighbourhood of London. The same observer detected among about 1200 flies of the gregarious species . 1 pl: i'lotIir1'.i: (C'-ynips) radicis not a single male. In many thousands of Cynipids, representing 28 species, llartig failed to discover any male. Von Schleetendal, on the other hand, between 24th April and 1st May 1871, from three galls of Ithoditcs rosaz, L., obtained in the pre- vious year, bred only ‘.2 females and 32 males. These males were of I latter part of May, when the females were in larger numerical pro- portion, were varieties of three kinds, partly resembling the females l in coloration.“ 'alsh9 ascertained with respect to the galls of the American Black Oak, that their growth commences in May, and is completed in a few weeks, and that near the middle of June about a fourth of them yield both male and female fully developed gall- flies of the species Cg/nips spongziﬁca, Osten-Sacken. In the re- mainder of the galls the lurvte do not attain their pupal condition till more than two months later, and the flies they produce, which appear about October, are all females. This iiutumnal brood lizis been experimentally ascertained to cause the generation of oak- apples in the following spring on trees not previously infected. Mr W. F. Bassett” considers that most, if not all, species of C3/nips are double-brooded, and that one of the two broods consists of females only. “There are,” he remarks, “so many onc-geiidcred species, that we may reasonably suppose each to be the progenitor of the equally numerous double-gendered species, whose relation- ships have not yet been observed.” Among the commoner of the galls of the ('3/2zz'pz'¢lw are the “ oak—apple” or “ oak-sponge” of Anclricus terminalis, F ab: the “ currant” or “ berr ralls ” of S’ )(tl]l(’f aster baccarum, L., above mentioned; and the “oak-spangles” of Z'em'oterus lentz'culcm's,“ Oliv., generally reputed to be fungoid growths, until the discovery of their true nature by Mr Frederick Smith ;12 and the succulent “ cherry-galls ” of ])r_2/opltcmta sciu‘ellarzs, Ohv. The “marble ” or “ Devon- shire woody galls” of oak—buds, which often destroy the leading shoots of young trees, are produced by C3/mps 1i'ollari,13 already alluded to. They were ﬁrst introduced into Devonshire about the year 1847, had become common near Birmingham by 1866, and two or three years later were observed in several parts of Scotland.“ They contain about 17 per cent. of tannin.“ On account of their regular form they have been used, threaded.on wire, for making ornamental baskets. The large purplish Mecca or Bussorali galls,” produced on a species of oak by Cymps ms(ma, I Vestw., have been regarded by many writers as the Dead Sea fruit, mad-apples (mala msana), or apples of Sodom (poma sodomitica), alluded to by osephus and others, Which, however, are stated by E. Robinson (132721. Ifesearclies in Palestine, vol. i. pp. 522—4, 3d__ed., 1861) to be the - - 7 singular fruit called by the Arabs Os/z.er, produced by the Asclepias gigcmtea or procem of botanists. What in Cali- . 1, fornia are known as “flea seeds ’ are oak—galls made by a 7 Zoologist, xix., 1861, pp. 7330-3. ' _ _ ‘_ 8 _]a},_,.e_.,.(,e.,-_ dc; I'g7-gins f. zulggvickau, 1841, p. .4. 9 A ' E t lo ' t, i. y P- - 1°  igdg. $'sLonl1on for the year 1873, p. xv. “ According to} Dr Adler, alternation of generations takes place be- tween N. lenticularis and bjpathegaster baccarum (see L. A. Ormerod, Entomologist xi. p. 34). _ __ 1* See VVeiitw0od, Introd. to the Mod. Clasnf. of Insects, 11., 1340, . 130. P 13 For ﬁgures and descriptions of insect and gall, see lvhitomulogist, iv.lp. 17 ; vii. p. 241 ; ix. p.857Ei; xiipblil. “ Scottish 1'a.lm'alist, i., 1 p. 1 '0. 15 Vinen, Journ. de I’harm.,ct de ,Clu'm., xxx.,_010S56, p. ‘.390 ; “ English lnk-Galls,” Pharm. Journ. 2d ser. iv. p. .>- . 15 See Pereira, Jllatcria Jllrrlica, ’vol. ii. ipt. i. p. 347; Plbarm. I Juu./~n., lst ser., vol. viii. pp. 422-4.
 * the normal coloration and shape; but some which appeared in the
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