216 
NOTICES OF SERIALS. 
Royal Institution of Great Britain. Miscellaneous—(Dr. Garreau) On the 
Formation of the Stomata in the Epidermis of the Leaves of the Spiderwort, and on 
the Evolution of the Cells in their Neighbourhood ; (H. and A. Adams) Descrip¬ 
tion of a New Genus of Bivalve Mollusca; (M. Tulasne) On the Dimorphism of 
the Uredinese. 
No. 80, August:—(W. J. Burnett, M.D.) Researches on the development of 
Viviparous aphides. This paper is extracted from Silliman’s American Journal 
for January, 1854, and being of the greatest interest, we give large extracts in 
the author’s own words :—“ Every naturalist is aware of the remarkable pheno¬ 
mena connected with the viviparous reproduction of Aphides or plant-lice; for their 
singularity has led them to be recounted in works other than those of natural 
science; and, from the days of the earlier observers, they have been the theme of a 
kind of wonder-story in zoology and physiology. I need not here go over the his¬ 
torical relations of this subject. The queer experiments and the amusing writings 
of the old entomologists are well known. The brief history of the general condi¬ 
tions of the development of these insects is as follows :—In the early autumn the 
colonies of plant-lice are composed of both male and female individuals; these pair; 
the males then die, and the females soon begin to deposit their eggs, after which 
they die also. Early in the ensuing spring, as soon as the sap begins to flow, these 
egg3 are hatched, and the young lice immediately begin to pump up sap from 
the tender leaves and shoots, increase rapidly in size, and, in a short time, come to 
maturity. In this state it is found that the whole brood, without a single exception, 
consists solely of females, or rather, and more properly, of individuals which are 
capable of reproducing their kind. This reproduction takes place by a viviparous 
generation, there being formed in the individuals in question, young lice, which, 
when capable of entering upon individual life, escape from their progenitor and 
form a new and greatly-increased colony. This second generation pursues the 
same course as the first—the individuals of which it is composed being, like those of 
the first, sexless, or, at least, without any trace of the male sex throughout. These 
same conditions are then repeated, and so on almost indefinitely—experiments hav¬ 
ing shown that this power of reproduction, under such circumstances, may be exer¬ 
cised, according to Bonnet, at least, through nine generations ; while Duvau ob¬ 
tained thus eleven generations in seven months, his experiments being curtailed at 
this stage, not by a failure of the reproductive power, but by the approach of winter 
which killed his specimens; and Kyber even observed that a colony of Aphis 
dianthi which had been brought into a constantly-heated room, continued to propa¬ 
gate for four years, in this manner, without the intervention of males, and even in 
this instance it remains to be proved how much longer these phenomena might 
have been continued.” We have then described the various observations of Dr. 
Burnett on the Aphis Caryse of Harris, and the details of the embriological deve¬ 
lopment of the so-called Viviparous aphides, so far as our author had enjoyed op¬ 
portunity for their study. “We will now refer for a moment to the special points 
which have here been made out. In the first place, it is evident that the germs 
which develop these forms are not true eggs. They have none of the structural 
characteristics of eggs, such as a vitellus—a germinative vesicle and dot; on the 
other hand, they are, at first, simple collections, in oval masses, of nucleated cells. 
Then, again, they receive no special fecundating power from the male, as is the 
necessary preliminary condition of all true eggs ; and, furthermore, the appearance 
