Effects of Castration in Insects 399 



Three series of operations were performed: first, the removal of 

 both gonads; second, the removal of the gonads together with 

 the gonad-ducts; and third, the transplantation of testes into 

 female and of ovaries into male caterpillars. The transplantation 

 of ovaries was more easily performed than that of the testes. In 

 these cases the transplanted organs not only developed to their 

 normal size, but the ovaries in some cases even united with the 

 male vasa deferentia. In one case a single transplanted ovary 

 united with one of the vasa deferentia, and as the testes of the 

 opposite side developed, an artificial hermaphrodite was produced. 

 Meisenheimer describes the results of his operations as follows: 

 "Oudemans' and Kellogg's experiments established the fact that 

 the removal of the gonads exerts no influence on the secondary 

 sexual characters. My results agree with these to the extent that 

 in my experiments the originally male caterpillar always produced 

 a male moth, the female caterpillar a female moth. The general 

 habitus of the respective sex was always perfectly preserved, both 

 in the form of the body, the structure of the antennae and the color- 

 ation of the wings, and this was true of the operations, both in 

 the case of the castrated moths and of the artificial hermaphrodites. 

 But on examining, in a comparative way, the material obtained, 

 a certain effect of the operations seems, nevertheless, to be notice- 

 able. The moths subjected to the two kinds of operation may be 

 arranged in series, which in the males vary from dark to light 

 forms and pass over in the females from a whitish to a darker 

 color." But, as Meisenheimer observed, there is considerable 

 color variation in both sexes of normal gypsy moths, and this was 

 true also of his control series, though he believed the variations 

 to be greater in those developed from operated caterpillars. The 

 specimens with transplanted organs, however, showed no greater 

 modification than those of the castrated series. It is especially- 

 noteworthy that in the cases of transplantation there was no 

 change in the copulatory or other organs, though these had not 

 yet developed at the time of operating. Hence, although Meisen- 

 heimer made artificial hermaphrodites, he did not succeed in 

 producing artificial gynandromorphs.^ 



* Unfortunately I was unable to secure a copy of the first part of i\feisenheimer's final mono- 

 graph ('09) till after the manuscript of my paper had gone to press. The review here given of 

 his experiments is, ther.rfore, inadequate. 



