462 STEFAN KOPEC! 



THE DEVELOPMENT OF IMAGINAL EYES THE GERMS OF WHICH 



HAVE BEEN TRANSPLANTED ON THE ABDOMEN OF 



CATERPILLARS 



The transplantation of the eyes in vertebrates has been ac- 

 comphshed by Uhlenhuth ('12, '13), who grafted larval eyes of 

 salamanders and newts on other specimens of the same species. 

 He convinced himself that the eyes undergo further evolution 

 after certain transitory processes of atrophy. In order to render 

 the independence of the development of the insectal eye still 

 more striking, I attempted the transplantation of the germ of eyes 

 to the abdomen, i.e., to surroundings which are heterogeneous 

 from an anatomical point of view. I deprived seventy-five cater- 

 pillars of the whole lateral part of the head, on which all their 

 ocelli are situated. Johansen ('92) has shown that the material 

 for the imaginal eye is contributed by the hypodermis between the 

 larval eyes, which are to be found on the chitinous plate removed. 

 I then inserted this plate into a large wound made on the fourth 

 abdominal segment of the same caterpillar by the amputation 

 of one of the paired orange-yellow warts. After a few hours 

 the plate had been well fixed in the new position by means of 

 coagulated blood. 



Out of forty-one pupae obtained from this series of experi- 

 ments, fifteen had distinctly demarcated, tiny hill-like con- 

 vexities in the place where the plate had been grafted. These 

 convexities differ from the integument of the other segment in 

 that they have a more glossy and deeper hue. In thirteen of the 

 moths which emerged from these pupae, a very distinct imaginal 

 eye, in most cases of normal size, was found on the corresponding 

 abdominal segment (fig. 6, tr. e.). The eyes were more or less 

 hemispherical, sometimes somewhat wrinkled and divided by fur- 

 rows. The histological structure of these eyes differs in no way 

 from that of normal eyes. We need only note that the height of 

 the ommatidia was reduced and that there was a proportional 

 shortening of their components. This detail was no doubt 

 connected with the abnormal tension and pressure in the new 

 surroundings of the eye which influence the developing organ. 

 Here also the grafted eyes had a well-developed 'nerve-bundle 



