334 



STEFAN KOPEC. 



recent researches on the development of the Malpighian tubes in 

 moths, the cells of the tubes of full-grown insects' are derived 

 directly from the cells of the larval tubes through certain physio- 

 logical and morphological metamorphosis. (Cf. paper of Samson, 

 '08.) By grafting fragments of the larval Malpighian tubes into 

 the head or thorax, I hoped to solve the problem as to whether the 

 metamorphosis of these tubes might occur normally, in anomalous 

 surroundings, even in the absence of a connection between the 

 tubes and the intestine. Smaller or larger parts of the tubes taken 



c 



from various regions were grafted into the head or the thorax of 

 the same caterpillar after the last moult of the animal : some of 

 the caterpillars operated upon had just accomplished this moult, 

 others had lived already 10 or n days after the last moult. In 

 other cases the Malpighian tubes were transplanted from female 

 caterpillars 10 days after their last moult into other caterpillars 

 2 or 3 days after this moult. After a few days the ends of these 

 implanted parts were healed up, and so the contents could no longer 

 come out. In the adult insect or pupa I several times succeeded in 

 detecting microscopically the presence of the implanted tubes, 

 which were here not united with the intestine. The cells of the 

 tube which developed in the head or the thorax (cf . Fig. A in text) 

 exhibited different characters from those observed in the cater- 



