Dr. F. Plateau on the Production of the Sexes in Bees. 253° 
lastly, in 1864 and 1865, M. von Siebold himself and M. 
Leuckart paid attention almost simultaneously to this singular 
fact, which is far from being rare *. 
I shall not enter upon this subject in much detail; it will 
be sufficient for me to say that in the androgynous bees 
there is a mixture of male and female characters varying from 
one individual to another, and which is met with in a number 
of organs both internal and external; very often we find 
simultaneously, on each side of the body, a few testicular coils 
and a few ovarian tubes, a well-developed male copulatory 
apparatus, and a sting, although the sting is wanting in the 
male. According to M. Leuckart all the hermaphrodite indi- 
viduals (of which he examined about fifty) must be regarded 
as workers presenting certain male characters. 
Here, therefore, we have bees in which the genital and 
other organs have been developed at once in the male and in 
the female direction—an evident proof that the larva has no 
sex before a certain period (the sixth day), and that an influ- 
ence which exists outside it causes it to deviate subsequently, 
either towards the male or the female type. 
Moreover certain animals, such as the Aphides, according 
to the beautiful investigations of M. Balbianit, of which M. 
von Siebold likewise says nothing, commence by having the 
two sexes united and in the same state of development. The 
viviparous Aphides are and remain hermaphrodites: in the 
oviparous Aphides, when the embryo is to become a female 
insect, the male organs retain their rudimentary character, 
while the female organs increase; on the contrary, when the 
individual is to be a male, the female part of the original her- 
maphrodite apparatus becomes transformed into a true testicle, 
the cells which it contains becoming fusiform follicles filled 
with spermatic corpuscles. Finally, the male apparatus does 
not disappear, and exists, after birth, in the oviparous indi- 
viduals of both sexes with characters which scarcely differ in 
any respect from those which it presents in the viviparous 
Aphides. 
To return from this to the causes which may determine the 
formation of the sexes in bees. It is possible that M. Landois 
* Von Siebold, “Ueber Zwitterbienen,” Zeitschr. fiir wiss. Zool. xiv. 
p. 73; Bibl. Univ. Archives, xx. p. 64. Leuckart, “Ueber Bienen- 
zwitter,” Bericht iiber die Versammlung deutsch. Naturf. und Aerzte, 
1865, iii. p. 173; Bibl. Univ. Archives, xxv. p. 172. 
+ Comptes Rendus, tome Ixii. pp. 1231, 1285, 1390; Ann. & Mag. Nat. 
Hist. ser. 8. xviii. pp. 65 and 106 (but see M. Claparéde’s observations 
on Balbiani’s researches, Ann. des Sci. Nat. 5¢ sér. vii. p. 21, and Ann, & 
Mag. Nat. Hist. ser. 3, xix. p. 360). 
Ann. & Mag. N. Hist. Ser. 4. Vol. 11. 18 
