334 Mr, C. F. M. Swynnerton's Experiments 



Mab., Acraea nafalica, Boisd., Byhlia ilithyia, Drury, 

 Mylothris rueppelli, Koch, aBeJenois, Leuceronia thalassina, 

 Boisd., Papilio echerioides, Trim., a.nd Rhopaloca7npta libeon, 

 Druce, It seemed that the Acraeas gave a little more 

 trouble, ^^^th their juice, than did Amauris \^^th its pungent 

 smell, yet this did not save them even for a moment. 

 That Amauris in time may have been better protected 

 than Leuceronia (and probably others) seemed to be sug- 

 gested by the slowness with which the ants would progress 

 with it, " spending as much of their time in feeling over the 

 surface of the butterfly as in carrying it." The froth- 

 masses of Rhodogastria bubo and the bay-leaf-scented 

 filaments of the larva of P. demodocus were only mo- 

 mentarily and locally deterrent, and the sting of the 

 hive-bee not at all. The Zonocerus with its (to us) 

 nauseous smell and its ill-effects on vertebrates eating it, 

 was naturally more slowly dismembered than the smaller 

 species used, but that was all. Quite unprotected also, 

 apparently, were beetles Himatismus, Systates, and the 

 Elaterid, the cockroach, the hymenopterous larvae, and 

 adult Musca domestica. A hungry cattle-tick was taken, 

 though full ones, on another occasion, were all refused; 

 but a very interesting incident in the experiments that 

 follow should be seen in this connection. 



The acceptance of vegetable-matter (banana) was in- 

 teresting, as was the fact that even partly-disabled 

 Acraeas — not the most active of butterflies in any case — 

 were able to escape for a time from the drivers. With 

 power of flight they should never be taken except when 

 asleep. This consideration, with the special repugnance 

 shown to eggs and very young larvae in the experiments 

 still to be described, suggests a very beautiful instance of 

 the probably universally obtaining principle of compensa- 

 tion and complementation and of the fact (implied therein) 

 that an animal's defences may vary greatly at different 

 stages of its existence, one defence being donned in pro- 

 portion as another is doffed, and vice versa. Thus in both 

 Acraea and, say, Papilio dardanus, numbers and intrinsic 

 nauseousness, at their height in the egg-stage (assuming 

 the experiments to be reliable), and then most necessary, 

 are gradually exchanged, in the first case for an ever- 

 growing supply of protective fluid, in the second for an 

 ever-increasing procryptic element in the coloration, this 

 culminating in the extraordinarily complete resemblance 



