228 



BIOLOGICAL LECTURES. 



ing moths, a very good pair by way of illustration, show a 

 broad bridge of union extending over the abdominal region 

 from the first to the fourth segments. 



Two individuals united by their dorsal thoracic regions are 

 shown in Fig. 5. The posterior ends are turned in opposite 

 directions. This specimen, of no very great interest otherwise, 



FIG. 5. Operation of the third category, a, united pupae and b, united imagines 

 of S '. cecropia. 



illustrates the non-expansion of the wings of one moth, while 

 those of the other were of almost the normal extent. 



Two moths can be fused by the wings by exposing the roots 

 of the pupal wing cases and uniting the wounds. In the one 

 successful case obtained both moths failed to extend their 

 wings, and no observations upon flight could be made. 



In conclusion, it has been shown that it is possible to pro- 

 duce, by placing and keeping together the wounds of two sec- 

 tioned pupae or fragments of pupa, a very intimate coalescence 

 between the components. This coalescence is dependent upon 



