THE EUGSTER GYNANDROMORPH BEES 



PROFESSOR T. H. MORGAN 

 Columbia University 



About fifty years ago von Siebold wrote his classic 

 paper on "Zwitterbienen" in which he gave an account of 

 anomalous bees that appeared in considerable numbers in 

 a hive of a bee breeder, named Eugster, in Constance. 1 

 The particular interest that attached to the case was not 

 only that a bee might be partly male and partly female, 

 mixed in all manner of proportions, but that they were 

 hybrid bees as well, the mother belonging to the race of 

 Italian bees, while the father or fathers were German 

 bees. Von Siebold did not state in his paper whether the 

 male parts of the gynandromorph were like the father, or 

 were hybrid, or were like the mother. In fact it was not 

 until 1888 that the importance of such information was 

 realized. In that year Boveri described a result that he 

 had obtained with the eggs of the sea urchin, in which as 

 a result of delayed fertilization (or of some irregularity 

 in the penetration of the sperm into the egg) the sperm 

 nucleus fused 'with one of the two nuclei resulting from 

 the division of the egg nucleus. In consequence half of 

 the nuclei were derived from the egg alone, while the other 

 half of the nuclei arose from the union of the paternal and 

 a maternal nucleus. If now, as other evidence seemed to 

 show, one nucleus in the bee produces a male and two 

 nuclei a female, such a partially fertilized egg should be 

 male on one side and female on the other side of the body 

 of the resulting individual. In this way, Boveri pointed 

 out, the Eugster gynandromorphs might have arisen. 



In 1905 I pointed out that the Eugster gynandromorphs 

 might also be accounted for by means of another hypoth- 

 esis. If two (or more) spermatozoa should enter the egg, 

 one of them might unite with the egg nucleus while the 



