166 LECTUEES ON BIOLOGY 



distinguish between them. In other districts Elaps corallinus 

 is represented by a related species which has black transverse 

 bands bordered with yellow seams. This characteristic is again 

 faithfully repeated by the non-venomous mimicker. 



Such cases of mimicry appear more remarkable still when 

 the animals concerned belong to widely distant classes. In 

 New Pomerania was recently found a sea-snake, Pla turns 

 colubrinus, a venomous, strikingly coloured animal of 2 to 3 

 metres. This is mimicked by a fish, Ophickthys colubrinus. 



Let us conclude with an instance in the life of butterflies. 

 On the banks of the Amazon one may frequently observe gaily 

 coloured butterflies (Heliconiidse), which lazily flutter about in 

 large swarms. Though these butterflies are visible at great 

 distances and even appear to exhibit a desire to be noticed, they 

 are almost never molested by enemies ; it may sometimes happen 

 that a young, inexperienced bird attacks one of them, but it will 

 never repeat the mistake, for these butterflies possess such an 

 objectionable smell and taste that they are avoided by all 

 animals. Many years ago Bates observed that these swarms 

 of Heliconiidse were regularly invaded by other butterflies which 

 belong to a widely different genus, the Pieridse or " Whites," and 

 furnish tasty food. But as the Pieridse copy the Heliconiidse, not 

 only in shape and colour, but also in their awkward manner of 

 flight, and live in their society they, too, escape persecution. Who 

 would, after hearing of such instances, of which many more 

 could be adduced, doubt the great importance of protective 

 colouring and mimicry? Nevertheless, we are confronted, on 

 accurate examination of the facts, by many objections, and will be 

 driven to admit that in the consideration of cases of mimicry 

 many gross mistakes have been made. Because an animal has 

 the colour of sand or looks like a leaf it does not follow that it 

 derives advantage from this characteristic. Because one species 

 of butterfly for instance, the Yellow Underwing mimics in 

 colour and design dark, lichen-covered parts of a wall, this is con- 

 sidered a splendid case of adaptation, causing much astonishment 

 in every Natural History Museum. But unfortunately for the 

 theory this butterfly settles in nature by preference on well- 

 lighted places, where it is easily distinguished from its sur- 

 roundings. 



