74 THE ORIGIN OF GYNANDROMORPHS. 



Description. — The mosaic was female except for the head, which was 

 entirely male. The left eye was eosin (male type) and the right blood (i. e., 

 it was not eosin-blood compound). 



Explanations. — A blood X egg was fertilized by an eosin X sperm. If at 

 some cell division in the futm^e head region of the very early embryo somatic 

 reduction occurred, that is, if the eosin X went into one cell and the blood 

 into the other, neither dividing, both cells would produce male parts with 

 the eosin and blood type eyes. The result may, however, be explained in 

 another way, viz, both chromosomes divided, but in an early cell division 

 double elimination occurred. One daughter chromosome from each X was 

 caught by the elimination plate, and the remaining X's were left, one in each cell. 



No. II. 1916. Hyde and Powell. 



Parentage. — The mother had white eyes and wild-type wings; the father 

 had red eyes and truncate wings (second chromosome). 



Description. — The gynandromorph had a white eye and a truncate wing 

 on the left side and a red eye and wild-type wing on the right side. The fly 

 was female in other parts and when mated to a white-eyed brother produced : 

 red females, 75; white females, 70; red males, 65; white males, 65. 



Explanations. — An egg containing a white-bearing X was fertilized by a 

 red X sperm. Elimination of a maternal X left the male parts with the 

 white X. The appearance and disappearance of truncate are so erratic that 

 in this case no safe conclusion can be drawn from the appearance in only the 

 male side. One might suppose that the male and female sides, differing in 

 their X chromosomes, also differ in a sex-linked modifier for truncate. 



GYNANDROMORPHS AND MOSAICS IN BEES.^ 



The domesticated bees have furnished many cases of gynandro- 

 morphs, both in hives supposedly pure and in hybrid communities. 

 An excellent review of the recorded cases is given in Miss Mehling's 

 paper of 1915. The earliest description is said to be that of Lau- 

 bender in 1801. Lefebure in 1835, Donhoff in 1861, Smith in 1862, 

 and Menzel in 1862 described gynandromorph bees. Widespread 

 interest in the subject was aroused by the discovery of many gynandro- 

 morphs in the stock of an apiarist, Herr Eugster, in Constance. 

 Menzel first reported on this occurrence. It was, however, von Sie- 

 bold's account of the Eugster gynandromorphs (1868) that brought 

 the subject to the general attention of zoologists. He gave not only 

 a description of many of these bees, but dissected them also, and de- 

 termined the correspondence or lack of correspondence between the 

 internal sexual organs and the external sex characters. In this hive 

 there was a queen of the yellow Italian race of bees (Apis ligustica) 

 fertilized by a drone of the darker German race (Apis mellifico). Her 

 sons were Italian, which is the expectation for this combination. After 

 the death of the queen, another queen of ''dark color" was present 

 in the stock. She also produced some gynandromorphs. 



^78 species of Hymenoptera in which gynandromorphs have been described are listed by 

 Enderlein, including Tenthredinidse, Braconidae, Proctotrupidae, Ichneumonidae, Formicidse, Mutil- 

 lidae, Crabonidse, Scoliidae, Pompilidse, Vespidje, and Aphid® (11 families in all). 



