254. QUARTERLY CHRONICLE. 
has waited since the time of the illustrious observers 
who first pronounced in favour of the hermaphroditism 
of these creatures. He believes that this state is the 
normal condition of the Aphides throughout the viviparous 
period of their existence, and that, under certain determinate 
conditions, a separation of the sexes is effected, and their 
mode of reproduction reverts to the law common to the gene- 
rality of species of animals. 
The ovary of the viviparous Aphis is minutely described 
by the author, and the changes undergone by the ovum or 
pseud-ovum, in its earlier stages, in the first part of his 
paper. In the second, the embryonal development is entered 
upon, and the evolution of a seminal vesicle and two male 
glandular cords is described. The seminal corpuscles are 
stated to be developed from larger coloured cells which con- 
stitute the mass of the male organs situated in the vicinity 
of the ovaries. They have an amceboid form, and sometimes 
break up into small, unequal bacilli, ‘(005 mm. in length. 
M. Balbiani states that several times he has succeeded in 
seeing some of these corpuscles in the ovarian tubes, or 
forming small groups at the bottom of the terminal chamber 
of the ovigerous sheaths.—The third portion of the paper is 
devoted to the consideration of the oviparous-sexual Aphides. 
Up to the period of birth, the development of both oviparous 
and viviparous Aphides is stated to be the same. It is only 
when their development has become considerably advanced 
that the first tendency to the separation of the sexes is ma- 
nifested. The separation is not effected by the atrophy of 
one of (what M. Balbiani considers to be) the sexual appa- 
ratuses. The male apparatus is said not to disappear, but is 
found after birth, in individuals of both sexes, with characters 
scarcely differing from those which it presents in the vivi- 
parous Aphides. M. Balbiani says that this male embryonic 
organ must not be confounded with an ordinary testis; but 
he will not say what it is until another occasion. He main- 
tains that this male organ arrives at maturity even in the 
females which are to produce eggs in the usual manner, to be 
fertilised by copulation, and that it, in some mysterious 
manner, fecundates the ovum within the female before copu- 
lative fertilisation has occurred. It really would be very 
desirable that we should hear a little more about this extra-_ 
ordinary male organ, which is not a testis, and which never- 
theless is said to impregnate the ova of viviparous and ovi- 
parous Aphides, which possess it. Surely it is not correct to 
apply the term hermaphrodite to a female simply because she 
may possess this very questionable organ. Like too many of 
