THE ORIGIN OF GYNANDROMORPHS. 75 



Several other descriptions of gynandromorphs in bees have been 

 published (see Mehling, p. 174, and Dalla Torre and Friese, 1898). 



There are certain facts in connection with sex determination in the 

 bee that are almost unique and give an unusual interest to the situa- 

 tion. The queen has the double set of chromosomes which is 

 reduced to the single or haploid number in the ripe egg, after two 

 polar bodies are extruded. If the egg is fertilized it gives rise to 

 a female (queen or worker), but if the egg is unfertilized it produces 

 a male (drone). The male has only the single set of chromosomes. 

 One set of chromosomes, then, produces a male, two a female; but 

 whether sex is the result of special genes carried by one or two sex 

 chromosomes has not been determined. Corresponding with the 

 single (haploid) number of chromosomes in the male, the spermato- 

 genesis shows certain special features. The preparation for the first 

 division takes place, and only a small non-nucleated piece of proto- 

 plasm is pinched off at one pole of the cytoplasmic spindle. Prepara- 

 tion for a second division follows and the chromosomes separate into 

 two groups, but the cytoplasmic division is very unequal and only 

 one of the nucleated cells that results becomes a functional spermato- 

 zoon. That at the second division an equational division of the 

 chromosomes occurs is probable, for in the closely related wasps the 

 second division takes place normally (according to Mark and Cope- 

 land) and two spermatozoa are formed, each with the single number 

 of chromosomes. Since in the male the haploid number of chromo- 

 somes must be supposed to be present, it might have been anticipated 

 that his nuclei would be half the size of those in the corresponding 

 parts of the female, as happens in the sea-urchin egg when haploid 

 and diploid nuclei occur in different regions of the same embryo. An 

 examination of this relation by Miss M. Oehninger has shown, how- 

 ever, that no such difference is present; hence what might have been 

 a means of determining the constitution of the male and female parts 

 of the gynandromorph is lacking. 



Von Siebold found the male and female characters combined in 

 many different ways in his gynandromorph bees, much as we find them 

 in Drosophila. In some cases one side was male, the other female; 

 or the anterior end might be like that of one sex and the posterior 

 like that of the other; sometimes different regions of the same organ, 

 such as an eye, leg, or antenna, might contain both male and female 

 regions. The normal worker has a sting, the male is without this 

 organ. In the gynandromorphs the sting was present if the abdomen 

 was like that of the worker, but absent when the abdomen was like 

 that of the male. No definite relation was found between the super- 

 ficial characters of the abdomen and its contained gonad. Testis 

 and ovary might even be combined into one organ. Externally the male 

 genital apparatus might be present and ovaries and oviducts exist inside. 



