22 4 



BIOLOGICAL LECTURES. 



considerable bulge, noticeable even in the photograph, was 

 caused between the two portions of the compound abdomen. 



Altogether, thirty-two attempts were made to unite in nor- 

 mal proportions fragments from two different species; only one 

 was successful. A hinder portion of a. promethea was perfectly 

 coalesced with an anterior part of a cynthia. This specimen is 

 shown in Fig. 2. Apparently, a perfect moth with unexpanded 

 wings confronts the observer. The contour of the abdomen 

 shows no break whatever. A point to be particularly noticed 

 is that the part of the compound abdomen taken from the 



FIG. 2. Operation of the first category. Compound moth, wings, and anterior body 

 from cynthia ; terminal abdominal segments from promethea. 



promethea shows no trace of a red color, but is buffy, exactly 

 as the general ground color of the rest of the abdomen, that of 

 the cynthia. 



Summarizing, then, the results of the operations belonging 

 to this category, we find that out of twenty-nine cases where 

 the parts belonged to pupae of the same species, three imagines 

 were obtained. Where the fragments belonged to different 

 species, one out of thirty-two gave successful results. 



A second group comprises the operations where a compound 

 of two pupae in "tandem " was prepared ; that is, the posterior 

 part of the abdomen of one and the anterior part of the body 

 of another pupa having been sliced off, the remaining fragments 

 were joined on a long axis. Usually the abdomen from the 

 fourth to the terminal segment was cut away from the anterior 

 component, but in some cases the section was made as far back 



