634 



SCIENCE. 



[N. S. Vol. XXI. No. 538. 



Von Siebold had in fact a ease of this sort 

 in the famous Eugster hive from which he 

 obtained his material. Unfortunately his 

 statement in regard to the racial characters of 

 the gjmandromorphs is obscure. The follow- 

 ing quotation is the only reference that he 

 has made to the racial characters of these 

 bees. 



Die fiinf Jahre Konigen dieses Stoekes war eine 

 reine Italienerin und hatte nichts Auffallendes an 

 sich. Sie musste sich mit einer deutschen Drone 

 begattet haben, da sich aiisser reinen italienischen 

 Arbeitem auch noch viele Bastardai'beiter von 

 verschiedener Abstiifungen in demselben Stocke 

 befanden, wahrend die Drohnen dieses Stoekes ihre 

 reine italienischen Abkunft verriethen. Aueh die 

 Zwitterbienen [gynandromorphs] dieses Stoekes 

 besassen die Fiirbung der italienischen Race; doch 

 war dieselbe unter dem Einflusse der deutschen 

 Race hier und dort getriibt worden. 



In addition to the interest of determining 

 which of these alternative views is the true 

 explanation, there is, as I have pointed out, 

 an implication in my hypothesis of more gen- 

 eral importance. On my view the sperm- 

 nucleus alone produces male characters, just 

 as the egg nucleus alone produces male char- 

 acters. If established, therefore, my view 

 would show that in the bee the male and the 

 female nuclei are exactly equivalent as sex 

 determinants. Alone, either produces male 

 characters, united in the same nucleus, they 

 give rise as a rule to female characters. The 

 results appear, therefore, to be quantitative 

 and not qualitative. From this point of view 

 the male nucleus is not the bearer of the 

 female sex-characters (although both sexual 

 characters may be latent in each nucleus), 

 but combined the two nuclei give the char- 

 acters of the female. 



It is far from my intention to set one of 

 these hypotheses over against the other, and 

 to attempt to weigh their relative merits on 

 the grounds of probability. I have raised the 

 question not to invite discussion, but to appeal 

 to those who may have an opportunity to ex- 

 amine gynandromorphs from mixed hives. 

 Neither do I wish to appear to be propounding 

 a theory of sex-determination, that will apply 

 to other cases in which other factors than 



fertilization appear to determine the sex of 

 the individual. 



In the group of Lepidoptera it may seem at 

 first sight that neither Boveri's view nor my 

 own can explain the occurrence of gynandro- 

 morphs, because it is not the rule here that 

 unfertilized eggs produce males, although this 

 sometimes occurs. The discrepancy is more 

 apparent than real, for, even if female butter- 

 flies develop from parthenogenetic eggs, as 

 a rule, the same explanation used for the bees 

 can mutatis mutandis be applied. If, for ex- 

 ample, the egg nucleus alone, or the sperm 

 nucleus alone, produces female characters 

 then on Boveri's view when the sperm nucleus 

 unites with one of the products of the first 

 division of the egg nucleus the resulting cells 

 may also happen in some cases to produce 

 male characters (just as some of the fertilized 

 eggs become males). The other half of the 

 first division produces a female, on the theory, 

 and a gynandromorph results. Under such 

 circumstances the female side of the indi- 

 vidual would show the character of the race 

 to which the mother belonged, if a hybrid 

 gynandromorph should be produced. If on 

 the above assumption the united male and 

 half female nuclei should produce a female 

 instead of a male then both sides would be 

 female, and there would be nothing externally 

 to indicate that such an individual was dif- 

 ferent from an ordinary female. On my view 

 also a formal explanation can be offered for 

 the lepidopterous gynandromorphs. If the 

 united nuclei should happen to produce male, 

 and the single sperm nucleus should give rise 

 to female characters a gynandromorph would 

 result. In a hybrid of this kind of individual 

 the female characters would be paternal. If 

 the united nuclei happen to produce a female 

 (since fertilized eggs may produce either 

 males or females), and the sperm nucleus 

 also produces a female, then both sides will be 

 superficially alike, and nothing would indicate 

 that such a female individual had had an 

 abnormal origin.* T. H. Morgan. 



Columbia Uni\'ersity. 



* If male-determining and female-determining 

 spermatozoa exist the gynandromorphous condition 

 in the bee might also be accounted for on the 



