EXPERIMENTS UPON THE LEPIDOPTERA. 229 



the regenerative or wound-healing power of the tissues involved. 

 So great is this power that in a " defect " cecropia example, 

 where the abdomen had been cut away back of the fourth seg- 

 ment and a paraffine film thrown across, the entire wound was 

 covered by a continuous and tough skin. This wound was a 

 half an inch or more in diameter. 



It is more difficult to bring about a coalescence between 

 fragments of pupae belonging to different species or genera 

 than where the two components belong to the same species. 

 Out of 62 operations of the former category 7 cases resulted 

 favorably, about 11.2 per cent. From 95 operations of the 

 second kind, 14 were successful, a percentage of nearly 15. 

 The total number successfully brought through the metamor- 

 phosis was 21 out of 127 operations.. 



Considering the results in another way, the mortality among 

 the pupae of the first group described, parts united in normal 

 proportions, was greatest, the survivors being but 4 out of 

 6 1 6.5 per cent of the whole. The " tandems" come next, 

 with a total of 3 successes and 24 failures, n.i per cent; 

 the " twins," as would be expected, present the most favorable 

 figures, 14 out of 69, 20.2 per cent, pairs affording 

 coalesced imagines. 



In regard to the second point, namely, the possibility of 

 reciprocal color effect, the results are somewhat disappointing. 

 With the exception of the two cases of cynthia and promethea 

 fusion, no departures from the normal color occurred. In none 

 of the cases of twin fusion of two specifically different moths 

 was there the slightest indication of abnormal coloration. The 

 entire question, therefore, as to whether a true reciprocal color 

 effect can be produced awaits the verdict of future extensive 

 experiment. 



