THE AMERICAN ENTOMOLOGIST. 



109 



tlir spriuj;, <;.ii)es opi'ii and allows the iii'^octs to 

 o-.-apc into the open air. Wlieii White ElniSMic 

 |)l;iiitecl :h shade trees in large nuinljrrs in llir 

 neighhorliood of liou^es. and heeonie hadly in- 

 fested by tlie>o galls, (lie winged ilios tlial are 

 generated in sncli myriads intlie middle of snni- 

 mer often become a very serious miisance. Ileneo ; 

 il is \vorth while lor us to learn, that when sueli 

 trees bceome large tliey will cease to be attack- 1 

 ed in such manner.* 



There may probably be some i>f our readers wlio 

 niu> be desirous of breeding the gall-making in- 

 seds from the galls figured above, or I'roiu sucli i 

 (ithcr gall-as they may have tliomselves discover- 

 ed upon other plants. We would caution allsucli , 

 liersons not to bo deceived by a very common i 

 pliein)menon. Ucsidcs the true gall-makcr, they 

 will obtain from almost every gall, one or two, 

 md sometimes out oi t\\o d /en ])eitecll\ di-> 

 tin tin-C(t- lln ( \m11 Uloii^ to Iwodilki 

 int^ioups ind It \m11 oiiiclinies u (juiio -ouil 

 nsilii djle ku<mkd„( ot tnt(jmolog\ to dis- 



m^iii li them liom the \nilabk lulhoi- ol the 

 ^ dl tint 1 b \uj; ( \p iimcntdt mon I li( 

 ,i(nip> lb \ I I II ll in i\ 1 ltd ,ii(d i- 



I 11 )^^ 



1 t (UR 1 111 t I oiniliniL MM do eh il 

 hit) the j(\\\ nnkti, sometimes i dillLitnt t- 



II I- po—ibit to conceiM A\ e Iiim ilii id\ 

 mil 1 the In id ot tin I'lm lu n illou _ ill 



I 1 1 ltd to i-iiullOuctdtll gint will hdwdls 

 niid I tli( l<.i\( olthetidl \Mtli )iit intiiliiuu 



III iii\ w t\ with fill lit ilth (I ]jio-i(iil\ ot lh< 

 iiitKh lii„ti (ol' ^ml tlutnnkc tin ^illiiid 

 li\c-iii tin \ii\ I ntn 1 I 11 s,o i_iin in the 

 (I ot theOik 1] pk oftlii l.h kOik (.1 V ^) 

 III n is inmiiiti ( ill Ih (S,/ , , /,ni /, m 

 () ten >si(k(ii) whidi 1- 0( i ion ilh loiiiid m 



>ii-id(i ibh niimbus iii litih (ill- loLilidim 

 iiKdiitih undci (lie l\I(1ih1 mid ol this Oik 

 q pie wIkk it 1i\c in flit 1 ii\ i s( uc upon the 

 nb tantc ot (he ., ill ^Mth1lll li nibliii, in ui\ 



wise, the much larger tenant of the central cell 

 ili.il is the real gall-maker. From these little 

 cilU it escapes early in the summer through 

 small pin-holes, each of which opens into one of 

 the external cells; whereas the large hole (Fig. 

 7s. I)), through which the gall-maker escapes, 

 may be always traced to the central cell. Tii 

 both the above two cases the Guest-liy does not 

 molest the Gall-maker; and this is the more gen- 

 eral rule. But in certain other cases the larva 

 of the (iuest-fly, instead of living in a lioii-c of 

 his own, makes his way to the house ot the gall- 

 mukiiig larva, and after having destroyed him. 

 takes possession of his tenement. For example, 

 there is a large undescribed Guest (iall-gnat* 

 which, as we have clearly ascertained, treats the 

 author of the Oak-plum gall (Fig. 8ii, a), in this 

 scurvy manner; and an allied species (iSi/ner- 

 /ii-ii/j)ti((li(i,) operates in the same way upon the 

 ( ill makiii^ larva of the Oak-bullet gall (Q. 

 // f)(ilt"t litch). Still, even in such extreme 

 t i-i '5 a'> tlicst the Guest-fly does not cease to be 



I \ tgetable Iteder and a true Guest: for it is 

 oiih incidtnt illy, ami for the sake of monopoli- 

 zing tin upply of vegetable food, that he des- 

 ti \ the gall maker. Whereas, parasitic larvie 

 It ( d L\clusi\ ely upon the botlies of their victims, 



mil make no use whatever of vegetable food. 



Jiid P 1 I itic insects. These are usually 

 piite di tiiKt from the insects they infest, and 



II niu< h mine luimerous, both in the number 

 ol tli-lintt jiecies and in the number of individ- 

 u lis beloiigm >■ to each species, than the (iuest- 

 iii-i tts iheie are certain species that i>ecnliarly 



ittitk lh( Guest insects, and certain others that 

 I nliiu th( 111 elves to the Gall-makers, and it is 



)l((iidith lilt lotlecidetowhichofthetwogroups 

 till > slionld l)L' properly referred. Parasites he- 

 Ion^ lo a git it variety of difterent Families; but 

 those th It inlt st galls maile by Gall-flies (Cynips) 



iiid Gall gn its {CecidoiiHjid) most of them ap- 

 p it nil to II e great Chalets family. For in- 

 -I met tlicie are three very distinct C'/frtfcjs-flies, 

 till hn I of ivhich prey intlitt'erently upon the 

 _ ill miking 1 irvse of the two kinds of Oak-ap- 

 phsfignied ibove (Figs. 78 ami 79), antl may 



lien be touud in the central cell of the gall. 



1 he fiist ot these lives inside the body of its vic- 

 I nil is i„ tilt moi-e usual practice with parasites, 



iiid pioduif s a black and yellow fly (Deca(oma) 

 w ith I laigc black pat:;h on its glassy wings. 



I 111 tiond dtaches itself externally to the body 



I ll \i I mi. and produces a beautiful bright 

 tilli ^1 n ny (('al/i,„<,„ir) with uniformly 



