ENTOMOLOGICAL SOCIETY. 



23 



__--„!» The butterflies are not so well suited to these experiments as these large moths, 

 partly because of their status being higher than that of the moths, and in the case of those 

 which winter either in the larval or imago state, the chrysalis period is too short. 



fs^Naturally, failure resulted in a good many cases, the average of successful operations 

 amounting to about ten per cent. 



Fig. B. Operation of the second category. Union in " Tandem ' 



posterior. 



of P. Cynthia, anterior, and C. Promethea' 



The operations were of great variety, the anterior end of one pupa being joined to 

 the posterior end of another either of the same or of a different species, or they were 

 joined in tandems or in pairs back to back, while in one case the tip of the abdomen of 

 one moth was grafted to the upper side of the abdomen of another. One pupa had had 

 its head cut off and was still alive and the abdomens of some were cut off about the mid- 

 dle to see if any regeneration would take place. No cases have been successful where 

 the division has been made longitudinally through the centre of the pupse, and the nearer 

 this line is approached the fewer there are which are successful, and conversely the less 

 that is taken off the more likely are the subjects to survive. 



The modus operandi is to slice the pupre with a razor and effect the junctions with 

 melted paraffin. The paraffin ring cannot be removed, as the coalescence is only effected 

 between the interior portions, the two portions of the pupa case never uniting. The 

 paraffin ring naturally tends to prevent the imagos emerging and they have to be helped 

 out when they seem, from the papery condition of the pupa case, to be ready for emer- 

 gence, the case being picked off bit by bit. 



In general, the wings fail to expand and as a consequence the abdomen remains 

 distended by the hsemolymph. In some cases the wings, or a majority of them, expand 

 very well, one, perhaps, being aborted. In the case of a taudem junction, the anterior 

 one may expand and the posterior one not. In such a case the former had only lost the 

 tip of its abdomen, while the lower one had lost its head. In one case where two portions 

 of pupse were joined laterally, one eye in one part had coalesced with the neighbouring 

 one in the other part to form a common eye. As a rule, the operations greatly retarded 

 the development of the specimens. 



