14 NOTICES OF THE MEETINGS [Feb. 7, 
The true nature and relation of the individual polype to the 
compound whole is well illustrated by the propagations of the 
Aphides. 
By comparing with the diagrams of the metagenesis of the plant 
and polype, that of the Aphis, in which was represented the corre- 
sponding stages intervening between the ovum and the perfect male 
and female individuals of the Aphis, the analogy between these 
stages in the plant, the polype, and the insect, was shown to be 
both true and close. The microscopic fertilizing filament of the male 
Aphis answers to the microscopic pollen-filament of the male leaf or 
‘stamen.’ The ovum of the female Aphis to the ovule of the 
female leaf or pistil: by their combination the fertile ovum results. 
The same processes of cell-formation ensue, and the embryo Aphis 
is formed by the combination and metamorphoses of certain of 
these secondary germ-cells ; but it retains the rest unchanged in its 
interior, which may be compared with the cells of the pith of the plant, 
and with the cells in the corresponding more fiuid part of the pith of 
the polype. Under favourable circumstances of nutriment and warmth, 
certain of these cells repeat the process of embryonic formation, and 
a larval individual like that from the ovum is thus reproduced ; 
which is only not retained in connection with its parent, because the 
integument is not coextended with it. 
The generation of a larval Aphis may be repeated from seven to 
eleven times without any more accession to the primary pollen-force 
of the retained cells than in the case of the zoophyte or plant; one 
might call the generation, one by ‘internal gemmation ; ’ but this 
phrase would not explain the conditions essential to the process, 
unless we previously knew those conditions in regard to ordinary 
or external gemmation. 
At length, however, the last apterous or larval Aphis, so deve- 
loped, proceeds to be ‘ metamorphosed’ into a winged individual, 
in which either only the fertilizing filaments are formed, as in the 
case of the stamens of the plant, or only the ovules, as in the case 
of the pistil, We have, in fact, at length ‘ male and female indi- 
viduals,’ preceded by procreative individuals of a lower or arrested 
grade of organization, analogues to the gemmiparous polypes of the 
zoophyte and to the leaves of the plant. 
The process was described for its better intelligibility in the 
Aphides as one of asimple succession of single individuals, but it is 
much more marvellous in nature. The first-formed larva of early 
spring procreates not one but eight larve like itself in successive 
broods, and each of these larve repeats the process ; and it may be 
again repeated in the same geometrical ratio until a number which 
figures only can indicate and language almost fails to express, is 
the result. The Aphides produced by this internal gemmation, are 
as countless as the leaves of a tree, to which they are so closely 
analogous. 
