470 STEFAN KOPEC 



the respective haemal fluids of the two sexes." Crampton's 

 investigation itself, however, does not justify our drawing such 

 a conclusion; at the same time it is quite true, as we shall soon 

 convince ourselves. First, the united parts were relatively large 

 bodies, very thoroughly and abundantly supplied with blood, this 

 being different in each part; it seems to me very probable, 

 therefore, that in the cases given there was no thorough mingling 

 of the two haemolymphs in the artificially joined organism; 

 since it is quite possible that these did not mix at all, Crampton's 

 conclusion does not seem to me to be proved. Secondly, the 

 connection of the chrysalides was possibly made at too late a 

 stage for this supposed influence of one part on the other to be 

 \dsible. I tried, therefore, to verify Mayer's theory by a some- 

 what different method. At the same time my experiments were 

 intended to show the morphological and physiological self- 

 differentiation of the insect wing still more distinctly than it 

 has been shown in the experiments on the castration of cater- 

 pillars. (See below.) 



I removed the germs of the first right wing from male cater- 

 pillars of Lymantria dispar L. after their last moult, and in their 

 place I grafted a similar germ from a female caterpillar, and vice 

 versa. It was necessary that both caterpillars should be of 

 about the same age, so that the time of pupation of the one 

 operated upon would coincide most strictly with the time at 

 which the implanted wing of the opposite sex should attain the 

 stage of metamorphosis. Naturally, the fulfillment of this 

 condition was extremely difficult, and on the other hand the 

 metamorphosis of the grafted "^ing always occurs quite inde- 

 pendently of the organism on which it has been implanted. 

 Therefore, if the condition mentioned has not been fulfilled, the 

 implanted wing undergoes metamorphosis at a different time 

 than the caterpillar on which it is grafted and cannot easily 

 come forth and develop subsequently. If we take into considera- 

 tion also that the delicate germ was often injured during trans- 

 plantation, it is not astonishing that out of 120 specimens oper- 

 ated upon, the implanted germ developed into the pupal and 

 imaginal wing only in two cases. In these two cases we had to 



