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. Balbiani f, 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 difier 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. flir wiss. Zool. xiv. 

 p. 73; Bibl. Univ. Archives, xx. p. 64. Leuckart, "Ueber Bienen- 

 zwitter," Bericbt liber die Versammlung deutscb. Naturf. und Aerzte, 

 1865, iii. p. 173 ; Bibl. Univ. Archives, xxv. p. 172. 



t Comptes Rendus, tome Ixii. pp. 1231, 1285, 1390; Ann. & Mag. Nat. 

 Hist. ser. 3. xviii. pp. 65 and 106 (but see M. Claparede's observations 

 on Balbiani's researches, Ann. des Sci. Nat. 5® s6r. vii. p. 21, and Ann. & 

 Mag. Nat. Hist. ser. 3. xix. p. 360). 



Ann. & Mag. N. Hist. Ser. 4. Vol.W. 18 



