i893- ETIOLOGY OF VEGETAL GALLS. 365 



hearing, one of these entomophagous parasites (of which a type speci- 

 men may be seen in Callimome regius), discovers that a larva, condemned 

 to become the living prey of her progeny, is at a sufficient distance 

 from the surface of the gall to be reached by means of her fine 

 abdominal terebra or ovipositor, with which she accordingly proceeds 

 to puncture the gall, and on the body of the contained larva to 

 deposit a single egg. 22 



In due course this hatches out its living embryo, the direct enemy 

 of the legitimate possessor of the gall. This, feeding on the life-blood 

 of its host, grows into a well-fed larva. The larva, in its turn, 

 becomes a pupa, and the pupa an imago. Then, plying its mandibu- 

 late jaws, the mature insect proceeds to eat its way through the 

 woody substance of the gall ; and, clad in livery of golden sheen, with 

 bright and iridescent wings, enters upon a new stage of existence ; 

 and, strong in the instincts of its race, begins, as its parents did of 

 old, its insidious career of brigandage and death. 



Nor are the dangers of the legitimate possessor of the gall limited 

 by the operations of these sanguinary parasites. No sooner have the 

 galls begun to grow, and the normal larvae to feed upon the nutritive 

 stores with which they are provisioned, than another group of enemies 

 — near relatives of the Cynipidae — are introduced, unbidden, into their 

 dwelling-place, consume their food-substance, and shorten their lives. 

 These are the phytophagous inquilines, which, pauper-like, avail 

 themselves of others' labours, and live at their expense. Taught by 

 an innate faculty that the home of the cradled cynips is furnished 

 with provisions exactly suited to the early requirements of her own 

 offspring, the vegetable-feeding Synergus usurps the well-stored 

 sanctuary, and introduces there, not a single egg, as in the case of the 

 Callimome, but a dozen or more, whence issues, in due course, a tribe 

 of greedy larvae that — to quote M. Leon Dufour — " vont realizer le 

 ' sic vos non vobis' de Virgile." 



Thus the normal tenant of the gall, if not fortunate enough to 

 escape, finds itself in this most dire dilemma — either to be eaten alive 

 by its direct parasite, the Callimome ; or to die of starvation from the 

 action of its enforced messmate, the Synevgus. 



Nor are the ends of Nature yet fulfilled. The Inquilines, 

 battening on their stolen viands, suffer, like the rightful owner, from 

 parasitic enemies, which, consuming the invaders, become, in rough 

 and barbarous way, the avengers of the dispossessed and suffering 

 aborigines. 



But here, again, as if to punish wrong, and work retributive 

 justice, these parasites themselves are preyed upon by other parasites; 

 losing thus in turn their own lives, as they before had sacrificed the 

 lives of others. This is due, in great part, to the action of a new set 

 of spiculiferous parasites, lower in the scale of creation than the 



22 See M. Leon Dufour, Ann. desSci. Nat., 3rd series, Zool., vol. 1 



