252 Dr. F. Plateau on the Production of the Sexes in Bees. 



and which are at any rate in the same category, viz. a Siga- 

 Uonj a SylUsj an Autolytus^ an Amage^ and a Polycirrus. 



I may also remark, in passing, with reference to some of the 

 other known forms found in this collection, that the Halosydna 

 Jeffrey sii J Lankester*, is H. gelatinosa^ Sarsf, as men- 

 tioned in Dr. Gunther's Zoological Record for 1866, and that 

 I have not yet been able to make out a specific difference be- 

 tween Leodice norvegica, Linn., and Eunice Harassii, Aud, 

 & Ed.t 



In addition to the Annelids proper, there were some Plana- 

 rians, Ommatopleans, Borlasians, and a very remarkable form 

 allied to the latter group, with a bifid proboscis — ^besides a 

 boring SipunculuSj lodged in its cavity inside a fragment of 

 shell. 



XXIX. — On the Production of the Sexes in Bees. 

 By Felix Plateau, D.Sc. 



To the Editors of the Annals and Magazine of Natwral History. 



Ghent, Sept. 9, 1868. 

 Gentlemen, 



Having been occupied for a long time with investigations 

 upon the parthenogenesis of the Invertebrata, I have read 

 with eagerness the interesting notice by M. von Siebold " On 

 the Law of Development of the Sexes in Insects," in which 

 the learned Professor endeavours to refute the assertions and 

 experiments of M. Landois. 



The theories of Dzierzon and of Von Siebold, ingenious as 

 they are, and notwithstanding the numerous facts which are 

 cited in their support, seem nevertheless to be so much in con- 

 tradiction to our general knowledge of the reproduction in the 

 higher animals, that researches such as those of M. Landois 

 should be received with favour, and we ought to take care 

 not to reject them without having exhausted all possible argu- 

 ments in connexion with them. 



M. von Siebold, indeed, passes over in complete silence 

 some very important observations which seem to me to be 

 entirely in favour of M. Landois. Androgynous or herma- 

 phrodite bees have been remarked long since by a school- 

 master named Lucas ; and more recently this monstrosity has 

 been observed by MM. Doenhoff, Menzel, and Engster; 



♦ Trans. Linn. Soc. vol. xxv. p. 377, tab. 51. figs. 12,19, 26. 



t Beskriv. og Jagtt. &c. 1835, p. 63, pi. 9. fig. 25. 



X Hist. Nat. du Litt. de la France, ii. p. 141, pi. 3. fig. 5, 6, 7, 10, & 11. 



