RHOPALOCERA. 35 



attack. These lucky exceptions to the common condition of being 

 hunted down by hungry devourers are tlie Danaince and Acrceincc, 

 Sub-Families of Nymphalidm ;^ and they owe their immunity to their 

 being malodorous and unpalatable as food, and to their evidently being 

 recognised as uneatable by insectivorous animals. It is most interest- 

 ing to find these protected butterflies accompanied, wherever they are 

 prevalent, by species of difierent Sub-Families or Families which closely, 

 or even exactly, resemble them in form, colours, and markings, though 

 quite diverse in structure. The first entomologist who carefully ob- 

 served these " mimicries " in Nature, and arrived at a clear and 

 reasonable explanation of their meaning and origin, was Mr. H. W. 

 Bates, F.E.S., whose paper on the subject was read before the Linnean 

 Society of London in 1 8 6 1 , and subsequently published in the Trans- 

 actions (vol. xxiii.) of that body. Mr. Bates dealt with the very rich 

 material yielded by the butterfly fauna of Tropical South America, and 

 showed that while the models (protected species of Danainoi) were 

 most abundant and presented the ordinary fades of their family, the 

 mimickers were rare, and departed very widely from the appearance of 

 their nearest allies ; that the latter frequented the same spots as their 

 models, often flying among them ; and that the resemblance in life 

 was so exact as constantly to deceive his own experienced sight. He 

 observed that the very conspicuous and slow-flying Danaince were not 

 pursued by any of the ordinary enemies of insects to which they would 

 have fallen an easy prey, and detected the reason for this security in 

 the peculiar smell which they emitted, and thus indicated the obvious 

 advantage it would be to butterflies not so defended to resemble 

 Danainm closely enough to be mistaken for them, and so passed over 

 as uneatable. Demonstrating the identity in kind of these mimicries 

 with the protective resemblances to inorganic and to vegetable forms 

 so prevalent in Nature, he traced them similarly to the long-continued 

 action of natural selection, the chief operating agents being insecti- 

 vorous animals, which would continually destroy all those individuals 

 of the mimicking species least resembling those which are exempt 

 from persecution. Mr. Bates gave a list of no fewer than thirty-six 

 cases of mimicry known to occur among Tropical- American butterflies, 

 and in thirteen of these even the remote Moths (of the groups Castnice 

 and Bomhjces) supplied instances of mimicry. In one of these cases, 

 the Danaine Methona Psiclii is imitated by two other DanoAnoi of t,he 

 genus Ituna^ by the Pierine Lcptalis Orise, and by two Moths ; while 



1 There are also some similarly protected species among the Eeliconinm and Papilionince; 

 and these too have accurate imitators in other butterflies. 



2 These cases of apparent mimicry within the limits of the protected group itself present 

 much diflaculty. It might be supposed that the mimickers in these instances had for some 

 reason failed to acquire the distastefulness of their kindred, but this has not yet been shown 

 to be the case. Dr. Fritz Miiller, Mr. Wallace, and Mr. Distant have discussed the ques- 

 tion in Kosmos (1879-S1) and in Nature (vol. xxvi.) ; and Mr. Meldola (Annals and Mag. 

 Nat. Hist., December 1882) has published an interesting summary of the discussion, in 



