44 



niH CAME OI- HKIIISII 1-;AST Al'RKA. 



lliis inlinitc variation of colour and pattern been brought about soKly by sexual 

 selection > It is an explanation that possibly accounts for part of these colours, but 

 not as yet by any means is the theory proved beyond doubt. The action of climate 

 and environment, it may be found some day, have had more to do wilh the formation 

 of such colours and patterns than is generally suspected. How these conditions 

 act on given organisms does not seem to be known at present, but that they do act in 

 some way appears beyond a doubt. 



There is an instance, well known amongst entomologists, of eggs from the same 

 batch, hatched under different climatic conditions, producing the ordinary Brimstone 

 butterfly of the British Isles (G. Rhamni) and the exotic, orange-suffused Brimstone 

 {G. Cleopatra). Such an example is worthy of attention, and no doubt careful 

 experiments would be productive of other like results. If varying climatic con- 

 ditions can produce such difference in the products of the same batch of eggs, 

 how very much greater must be the change produced by long residence in a 

 different climate. However, it would be well to leave a subject on which one is 

 so ill-informed. 



Climatic influences and influences of environment have no doubt played a great 

 part in the coloration of insects. Until, however, more definite information is to hand 

 with regard to the effects of light and colour on living organisms, it seems that not 

 much more can be said. 



Next as to reptiles. These are generally bright-coloured, but very many appear 

 to be protectively covered. It would appear as if the colours of some snakes, 

 such as the green pit-viper and the puff-adder, are serviceable imitations of their 

 surroundings, and should be of use in concealing them from the secretary bird and 

 other foes, or of allowing them to remain undetected by their prey. The colour of 

 the green tree-frog, too, should serve to conceal his presence amongst the leaves 

 from the insects he wishes to catch. Other instances amongst reptiles are found, 

 such as with chameleons and some of the lizards. As reptiles are in the habit of 

 remaining perfectly stationary for long intervals, such protective coloration should be 

 of great value to them. 



The crocodile, although generally recognisable by the expert human eye, must 

 frequently escape observation from other animals, remembering always the difficulty 

 animals have in detecting any object remaining quite still. His likeness to a floating 

 log, perhaps, even deceives fishes upstream of him, for they are slow to see 

 stationary objects, rapidly as they fly from any movements. I certainly think that 

 the colour, and to a large extent the shape, of the crocodile is brought about for 

 the purpose of enabling it to lie undetected by its prey. Putting aside, however, the 



