ENTOMOLOGIST AND BOTANIST. 



331 



As to the hyiiotliesis l)i-oachoil by Dr. Reinhnril,* that the 

 loi-m 17. aciculala is tlii' only Inic }xall-making form, ami that 

 \iiilh q . sponi'Jiia anil 17 inauh arc inquiliiious; that is siil- 

 liiiinlly rel'uti'il by the nefrativc fact that no form analagoiis 

 to tj aciculala can be obtained, alXer extensive trials repeat ed 

 llirotiiih several years, from the f;all Q. inanix. For if in 

 reality Cynipsq. inanisiii ameregnest-lly in the gall ii. inanis^ 

 where are we to lliul a gall-maker ilistinct from that species 

 1(1 proilue.e that gall ? I am quite sure that none such exists. 

 On the other haml, it is absurd to .sn|iiHisc that, of two un- 

 distinguishiible gall-llies, C. q. sjiontji/tca and C. q. inanis, 

 the lirst is ;i gnost-IIy and Ihe second a gall-niakcr. 

 IKi..' c, 1 



The alternative hypothesis mhanc.ed by Reinhard a.-, a 

 snlntion of the mysterious anomaly of <;. aciculala being the 

 dimorph.)Us v form of q. sponql/ica, namely that each of 

 llii'sc two forms is a distinct gall-making species, is of very 

 doubtful validity, for the simple reason that the galls that 

 produce Ihcsc two forms are very coniplicateil in their struc- 

 ture and jjifsent a number of very constant characters, and 

 are, notwithstanding, nnilistinguishablc the one from the 

 other. It is very true that there are certain polythalamous 

 galls, of very simple structure, being in fact little else than 

 a simple enlargement of a twig, which can scarcely be ilis- 

 liugui.slud from one another, allbough they arc the work of 

 dislin<-l gall-makers. Indeed, polylhalamous galls arc very 

 generally more dillicult to characterize Ihan monotlialainous 

 galls, because their shape .and ^i/.i' d.pcnil upon the number 

 of gall-nniking larv.ij that they contain, which will ofbn 

 vary frcuu two or three to two or three score . Mouolhalanrous 

 galls, on the contrary, are as dellnitely limited in size and 

 shape as are the great m.ajority of the ilill'erent siwcies of in- 

 sects; and moreover, as a rule, they present muidi more 

 numerous and more accurately distinctive characters than 

 do polythalamous galls. Now, the oak-gall that we .are now 

 concerned with— that of Cj/mjJS »/. spongifica—in amonolhabi- 

 mous gall, and is just as nnich individualized, and just .as 

 easily recognized, .as is an apple, a peach, or a jduni; and, 

 moreover, the galls that prodni'i' the autumnal ilimorphous( 

 finin (q acicuhila) occur upon the very sami' tree, and in 

 <-.ornpany with those that produce the vernal bisexinil form 

 (r;. sponijijica J '.•). 



Dr. I.'cinhard, in the paper already referred to (p 7), in 

 conllriinithm of his secoiul hypothesis of C. q. sponqijini and 

 (' q aciculala being each of Iheni true gall-makers, produc- 

 ing npini the same plant galls that are ap])arcntly, but not 

 really, identical, <iuotcs the following two Kuropean cases 

 of undistinguishable galls being produced upon the same 

 plant by distinct insects: 1st. Two exactly similar twig-galls 

 on blackberry, produced respectively by LaHoplera ruM and 

 niaslrophus rubi. Now, 1 am lamiliar with an uudescribed 

 N. A. twig-gall, Rubi nodus, Walsh jrs., prodncoil by an 

 und(scribe<l Lasioplera allieil to L aolidaginis, O S.npon 

 an American blackberry. This blackberry-gall is a simple 

 enlargementof the twig, u.sually hut not always on the part 



*./;ertiii BiUo^nol, Zaif^cAr, TX, p. 'J* 



adjoining a bud, and is also polythalamous; and, as it is 

 produced on the same genus of plants, on the same part of the 

 plant, and by the very same Cecidomyidous subgenus a.s the 

 Cecidnmyiilous blackberry-gall spoken of by Reinhard, it 

 may reasonably be inferred thai this hist is of a similar 

 nature. In that eyent, I can see nothing very astonishing in 

 its being scarcely ilistinguishable from a similar gall maile 

 on the sarni' part of the same jilant by a Diatlroplius. 2inl 

 The second case quoted by Dr. Reinluard is that of two un- 

 dislinguishable leaf-galls upon Qucro/s rem'*, jirodnced 

 respectively by Cccidomyia circinajis, Girauil, and Cynips 

 (neiiro/rnij) lanuijinosus, liirauel. Now, I cannot help sus- 

 jieiiing Ihat in this latter ciise there exists but a single sjiecies 

 ol' gall, nuidi' by Ihe gall-gnat, Cccidomyia circinam, and 

 oceasioindly tenanted by an impiilinousgall-tly, Nearolerus 

 latiutjinnsiia. 'Ihi' genus, or rather subgenus, Neuroleriia ot 

 llartig is said by ilartig himself, as quoted by Osten Sackon, 

 lo be sonu'times inqiulinous;* and 1 am now acquainted with 

 no less than three cases wlu're gall-llies arc inquilinous in 

 galls Hull I know for certaintobe made bygall-giuds. I have 

 alreaily publisheil one such cxse (Proc Ent. Soc. Phil. Ill, 

 p. .^)l,s); and I have since bred, on .June .Ith, 4 f Ccreplres 

 from the Cecidomyidous willow-gall, S. balalas, Walsh; and 

 from an undesc.ribcd twig-gall upcni Dogwood, produced by 

 an unclescribcd Lasioplera alliecl to L. solidaginis, O. S,, but 

 distinct lYom the si)ecies just now referred to as bred from a 

 blackberry gall, 1 bred, June 23rd, Iwo specimens J 9 of a 

 Synergus, both genera, Ceroplres and Synergus, being Cynijii- 

 dous anil notoriously inquilinous in their habits. Many 

 analogous cases of gall-makers and imiuilincs, behmging to 

 widdy distinct fanulies, being iiroduced IVom one and the 

 same gall have been recorded by me in my Papers on Willow- 

 galls (Proc. Ent. Soc. Phil 111, pp. .Iti-im, and VI, 233-2SS). 

 lint all doubts as to the <limor\>hism of the agamons Cynips 

 q. aciculala has, to my mind, been removed by a si'ries of 

 experiments which I conducted , after my Paper on that sub- 

 ject had been published in the summer of l.sBt. {Proc. Enl . 

 Soc. Phil. II, pp. 44:i-,500.) Of these experiments I will now 

 jtroceed to give the full history in all its details. The rcjulor 

 can then judge for himsilf how far my f:icls are to be de- 

 jiended on, and how far the inferences that I deduce fixim 

 those facts are the logical results from the premises. 1 shall 

 not be surprised, however, if, in spite of all Ihat 1 can say, 

 my theory is recidved with as great incredidity as that with 

 which I formerly recidved the important iliscovery (d' Wag- 

 ner, in regard to the vivii>arous reprodul^lion of the lame of 

 a certain gentis of Cecidomyidcc. 



On October 2'.lth and November fith, 18G4, I colonized a 

 number of these agamons gall-llies, that I had bred myself 

 from oak-apples, upon Ihrce different isolated black oaks, 

 that I knew to have not been previously iufesteil by thesi' 

 galls for many years back Two of these trees were very 

 liiige— say about'ij feet in diameter at the butt— and I placed 

 Ihe gall-llies upon one particidar overhanging bough of each 

 of them, and on no other ))art of the tree. Thi' third tree was 

 small— say I foot in diameter at the bnti— au'l I iilaced Ihe 

 gall-llies on Ihe trunk of this tree, al the p..iut wher.' Ilir 

 mam branches took their origin. 



On May 21, l.sfi.-i, 1 exanuned all these three Ireis. Thellrst 

 large tree had no galls at all on it. The second large tree 

 had produced four Q. spongifica .galls, partly on the very 

 bough on which I had jdaceil the gall-lliis in the preceding 

 autunm, and )>arlly on sonu^ boughs that iTunwdiately atl- 

 jcdned it. I eatinniled Ihat the portion of this last tree thns 

 occupied by galls did not fcn-m more than one-twentieth of 

 the whide tree; so that, even if We suppose that one or more 

 wandering Cynips q. aciculala hail llown on to Ibis tree from 

 the neighboring woods in the preceding autunm— ami this 

 insei.t, coming out as it does so late in the yiar. Hies svs re- 

 luctantly and as didly as a Plant-lonse— the chances arc 

 abend I!) to 1 that they woubl not have occupied Ihe particular 

 portion of it found to bear galls in the following spring. On 



• So; Proc. Ent. Sac. nit IV, pp 'Sn Had 330. 



