EYE PIGMENTATION IN INSECTS — BODENSTEIN 



29 



larvae on a medium to which ground-up Fucellia adults were added 

 (Snyder, F. M., personal communication). From all this there seems 

 little doubt that Fucellia implants, like those of the other genera, 

 release into the blood of their hosts a substance that is able to change 

 the pigmentation of the green eye toward wild type. 



The implanted Callitroga eyes release perhaps the smallest amount 

 of the diffusible substance as judged by the host eye-color effects in 

 this series. From the 15 available cases, only 4 showed a "medium" 

 effect, while the other animals showed a "weak" effect or none at all. 

 Yet the transplantation of a green eye disc into a Callitroga host 



Table i. — Summary of inter generic eye transplantations 



Host eye 



Total 



number Color of 



Donor Host of cases implant 



Callitroga Musca green 15 wild 



Sarcophaga Musca green 14 wild 

 Cynomya Musca green 7 wild 

 Phormia Musca green 8 wild 



Number 



Number 



Fucellia Musca green 

 Musca 



green Callitroga 



wild 



of cases Color of cases Color 



II changed 4 green 



toward 



wild 

 13 changed i green 



toward 



wild 



7 changed — — 



toward 

 wild 



8 changed — — 



toward 

 wild 

 4 green — — 



19 changed 19 wild 

 toward 

 wild 



demonstrates that this host must actually contain an appreciable 

 amount of the effective substance, for all the implants gave rise to 

 eyes with almost wild-type pigmentation. This experiment illustrates 

 that as far as host eye pigment intensity is concerned, not too 

 much reliance should be placed on the results of the "one eye disc" 

 transplantations. 



An attempt was also made to transplant eye discs from green Musca 

 into Cynomya larvae. This failed, because all the hosts died in the 

 pupal stage. Transplantations of late larval DrosophUa virilis and 

 Aedes aegypti eye discs into green-eyed Musca larvae were also un- 

 successful. Here the hosts withstood the operation, but the grafted 

 tissues degenerated completely. 



