226 [March, 



Presuming that the readers of this are acquainted with my theory 

 of the phases of evolution of monoic insects, I thus classify the phases 

 of the evolutionary cycle of Spathegaster laccarum, Linn. : 



1. Eggs of the fecundated female, and the larvae pro- 7 Founders. 



ceeding therefrom, in the hard autumnal galls \ {Pseudogyna fundatrix.) 



2. Winged emigrants without sex, all identical, having ^ _. . 



( Emigrants, 



a long spiral ovipositor with which the buds are r fn . \ 



V (P. migrans.) 



punctured (Neuroterus leniicularis) ) 



3. Egg-buds and larvae proceeding therefrom, which are V Gremmations. 



enclosed in a fleshy gall of the form of a gooseberry \ (P. gemmans.) 



4. Sexuated insects, Spathegaster baccarum, Linn., males ) Sexuated. 



and females \ (sexuata). 



Entomological tradition makes it difficult for the mind to adopt 

 the idea that a winged form, having an ovipositor, and furnished in- 

 teriorly with a store of eggs, prodigiously like an ovary, should be only 

 a larva which will afterwards be reproduced as an apod, vermiform 

 larva, which will lead on to sexuated forms. 



I admit that this is rather difficult to understand, and yet I have 

 before me, in my cabinet, a nymph of Cantharis vesicatoria, which 

 appears quite ready to burst and render the perfect insect ; eyes, feet, 

 and mandibles are visible, and yet, I expect, as with Meloe and Sitaris y 

 to see this pseudonymph stop in its development, again become a larva, 

 and only then undergo the new transformations which will end in the 

 perfect insect. 



Why, then, should T not admit among Aphides and Cynipidce a 

 winged form perfectly imitating the perfect insect, except as to the 

 genital organs, capable of suddenly producing a new larval form, which 

 will eventually become sexuated ? 



The fact is there, broadly : I do not attempt to explain it, but 

 I declare it boldly ; and every one may convince himself that a 

 single egg of Phylloxera or a single egg of Spathegaster will produce, 

 after a series of diverse forms, males and females ; and before these 

 sexuated insects appear, would be seen winged insects which have every 

 sign of the perfect form, except that they are all absolutely alike (in 

 their well-known phase), and that they are reproduced without having 

 any sex, by gemmation, sometimes with organs and modes of repro- 

 duction so like those of true females that if it were not for the absence 

 of a corresponding male form, and the nature of the product accruing 

 — all very different from the first larva of the founders, — they might 

 be taken, as till now they have been taken, to be true females. 



