PROTECTIVE MIMICRY 227 



of the wings are the same as those of the upper sides, 

 or at any rate are equally conspicuous. A peculiar and 

 frequently unpleasant smell has been noticed by all 

 observers who have studied these groups. It is pro- 

 bable that the same means of defence is present in the 

 other stages, and this has been proved in certain 

 cases (e.g; Acrcea horta, Trimen). The unpleasant 

 smell frequently resides in a clear yellow fluid which 

 exudes on the slightest pressure. 



Mr. Trimen ^ has also called attention to the fact 

 that the conspicuous butterflies and moths which 

 possess such qualities have a remarkably elastic struc- 

 ture, and can endure very severe pressure without 

 injury. The wings are so flexible that they can be 

 bent and distorted without breaking the nervures. 

 The insects can in this way often recover from the 

 mistaken attacks of insect-eating animals. Skertchly 

 also maintains, from his experience in Borneo, that 

 nauseous properties are accompanied by strong 

 vitality. 



There is, unfortunately, too little direct experi- 

 mental proof of the unpalatability of the specially 

 protected groups which are the chief models of Mimi- 

 cry. When, however, all the observations are brought 

 together they constitute a fair amount of evidence, 

 and there can be no doubt about the results of future 

 experiments. 



Mr. Bates mentions the glands near the anus 



» Loc. cit. pp. 498, 499. 



