Protective Eesemblances. 143 



of yellow, ash, brown, and red is found here, and in many speci- 

 mens there occur patches and spots formed of small black dots, 

 so closely resembling the way in which minute fungi grow on 

 leaves that it is almost impossible at first not to believe that 

 fungi have grown on the butterflies themselves ! 



If such an extraordinary adaptation as this stood alone, it 

 would be very difiicult to offer any explanation of it ; but al- 

 though it is perhaps the most perfect case of protective imi- 

 tation known, there are hundreds of similar resemblances in 

 nature, and from these it is possible to deduce a general theory 

 of the manner in which they have been slowly brought about. 

 The principle of variation and that of "natural selection," 

 or survival of the fittest, as elaborated by Mr. Darwin in his 

 celebrated " Origin of Species," offers the foundation for such 

 a theory ; and I have myself endeavored to apply it to all the 

 chief cases of imitation in an article published in the West- 

 minster Meview for IseV, entitled, "Mimicry, and other Pro- 

 tective Resemblances among Animals," to which any reader is 

 referred who wishes to know more about this subject. 



In Sumatra monkeys are very abundant, and at Lobo Ra- 

 man they used to frequent the trees which overhang the 

 guard-house, and give me a fine opportunity of observing their 

 gambols. Two species of Semnopithecus were most plentiful 

 — monkeys of a slender form, with very long tails. Not being 

 much shot at, they are rather bold, and remain quite uncon- 

 cerned when natives alone are present ; but w^heu I came out 

 to look at them, they would stare for a minute or two and then 

 make off. They take tremendous leaps from the branches of 

 one tree to those of another a little lower, and it is very amus- 

 ing when one strong leader takes a bold jump, to see the others 

 following with more or less trepidation ; and it often happens 

 that one or two of the last seem quite unable to make up their 

 minds to leap till the rest are disappearing, when, as if in 

 desperation at being left alone, they throw themselves fi'antic- 

 aUy into the air, and often go crashing through the slender 

 branches and fall to the ground. 



A very curious ape, the siamang, was also rather abundant, 

 but it is much less bold than the monkeys, keeping to the vir- 

 gin forests and avoiding villages. This species is allied to the 

 little long-armed apes of the genus Hylobates, but is consider- 



