1901.] on Mimetic Insects. 697 



converged was in other districts the model imitated, it might fairly 

 be assumed that the group in question was protected and that the 

 mimicry was in such a case Mlillerian. Thus among Coleoptera 

 the Lycidse, which appeared as it were to set the fashion in the group 

 exhibited, were in other districts the subjects of imitation and so 

 were probably more or less " protected." 



The Lecturer in conclusion dwelt upon the objections that are 

 sometimes urged against birds, lizards, &c. being the selecting agents. 

 He considered that the difficulty in this case was of the same nature 

 as that which attends the theory of selection by natural agencies in 

 general. Although it is certain that a large amount of extermination 

 is constantly going on in nature, in scarcely any case can it be said 

 that the actual agent or agents have been observed or the process been 

 seen in operation. Four groups of butterflies caught at large witb 

 damaged wings were shown on the screen, viz. a group of species 

 of various genera showing indiscriminate attack, a group showing 

 attack at the tips of the forewings, and two groups showing notches 

 on the hindwings. One of the latter, a group of Lycsenidse, was par- 

 ticularly interesting as illustrating the deceptive adaptation of the 

 tailed prolongation of the hind-wing with the eye-like spot above it, 

 so as to resemble the head end of the insect with eyes and antennae. 

 This observation, which had been recorded before, had recently been 

 confirmed quite independently by Mr. Champion Russell in a South 

 African Lycaenid, and the frequent capture of these butterflies with 

 wings notched just about the eye-like spot lent support to the view 

 that the deception was successful against the attacks of birds, the 

 insect escaping vital injury by the sacrifice of a small portion of the 

 wing. 



One example was shown illustrating the difficulty of detecting 

 selecting agents at work even where experimental conditions had been 

 imposed which undoubtedly favoured selective extermination. In the 

 course of a series of experiments by Professor Poulton having for 

 their object the testing of the relative immunity of the variously 

 coloured pupae of Vanessa urticse according as they were exposed on 

 surfaces with which their colours harmonised or not, it was found 

 that a large percentage of individuals out of harmony with their sur- 

 roundings was picked off by some foe, most probably a bird, leaving 

 only the tail attached to indicate where the chrysalis had been sus- 

 pended. Although hundreds of pupae had been removed in this way, 

 the most persistent observation had failed to reveal the enemy which 

 removed them ; on one occasion only did the observers suspect that a 

 bird was at work, but the tree on which the pupas were exposed was 

 too far off to be sure of the species. 



The Lecturer expressed Lis thanks to those who had helped to 

 furnish illustrations ; to Dr. Alfred Russel Wallace for the loan of 

 slides and to Professor Poulton for slides and for the free use of the 

 materials in the Hope Museum. All the groups illustrating the later 

 developments of the theory of mimicry had been arranged by Professor 



