KX 
was supposed to be derived; he suspected that von Tschudi had in his mind the old 
and exploded notion that pure oxygen was given off during the melting of snow, or 
that the water of melted snow contained an extraordinary quantity of oxygen. 
Insects, however small, would from the texture of their wings absorb heat very 
readily, and when placed on the snow they would by radiation give it off again, 
probably with equal rapidity; the meliing of the snow, the formation of a cavity, and 
the descent of the insect, would be the natural result; but he was not able to account 
for an insect sinking to the considerable depth of two feet, as mentioned by von 
Tschudi. He should like to ask Mr. Pascoe whether the diameter of the hole in the 
snow greatly exceeded the expanse of the out-stretched insect? He imagined it 
would not. 
Mr. Pascoe replied that the insects, when taken out of the cavities, were wet and 
limp, and their wings became clogged together, so that he could not speak with 
accuracy as to their admeasurement; he thought, however, that the breadth of the 
expanded wings would be nearly equal to the diameter of the hole. 
The President said that he also had noticed similar holes in the snow when 
_ crossing some of the Alpine passes, though at the time he bad not bestowed upon 
them the attention which it now appeared they deserved. 
The President called attention to a paper by M. Balbiani, published in the 
‘Comptes Rendus, June 4, 1866, in which the writer propounded a theory that the 
Aphides are true hermaphrodites. According to M. Balbiani’s observations, each ovarian 
tube possesses an enlarged end which contains a group of cells; one of these, which 
occupies the centre and is surrounded by the others, is the most important, “car elle 
représente élément générateur ou la cellule mére de tous les ovules qui, dans chaque 
gaine, sont destinés a se transformer en embryous;”’ the peripheral cells nourish the 
central one; when the ovule enters the ovarian tube, it possesses a germinative vesicle 
and spot; the latter soon disappears, and after it the vesicle also; during this time 
many nuclei become apparent in the surface of the vitellus, and condense round 
themselves the homogeneous substance of which it consists; these are the blastodermie 
cells, which at this period are not surrounded by any membrane; the cells increase in 
number so as to cover the whole egg; after awhile an opening commences at the 
posterior end, and from it some of the contents protrude like a hernia; a delicate 
membrane is then visible inside the blastodermic cells; the hernial portion forms a 
connexion with the epithelial cells, and, when this is done, the vitelline vesicle 
contracts inside the blastoderm and divides into two secondary vesicles, of which the 
posterior one adheres to the epithelium, while the other remains free ; these vesicles or 
cellules are the embryos of the sexual elements; the surface of each becomes covered 
with a generation of small cellules which grow and continue to develope others; the 
posterior group is male, the anterior (the free one) is female; the latter remain 
colourless and are smaller than the male cellules, which become green or yellow (this 
is the pseudo-vitellus of Huxley); the mother vesicle soon disappears, while the male 
one increases and constitutes a reservoir of fecundating corpuscles ; up to this time the 
embryonal development has not commenced, but from this pvint it proceeds regularly 
until the birth of the young Aphis. 
Prof. Westwood was reminded, by the mention of Aphides, of a circumstance 
which had recently puzzled him. He had at Oxford some rose-trees which did not 
grow in the spring, but had only lately thrown out shoots; no sooner did a shoot 
