o,2 The Colours of Animals. 



III. 



1. Let us now take a single group, and see how 

 far we can explain its various colours and markings, 

 and what are the lessons which they teach us. For 

 this purpose, I think I cannot do better than select 

 the larvae of the hawk-moths, which have just been 

 the subject of a masterly work by Dr. Weissmann, 

 from which most of the following facts are taken. 



The caterpillars of this group are very different 

 in colour green, white, yellow, brown, sometimes 

 even gaudy, varied with spots, patches, streaks, and 

 lines. Now, are these differences merely casual 

 and accidental, or have they a meaning and a pur- 

 pose ? In many, perhaps in most cases, the mark- 

 ings serve for the purpose of concealment. When, 

 indeed, we see caterpillars represented on a white 

 sheet of paper, or if we put them on a plain table, 

 and focus the eye on them, the colours and markings 

 would seem, if possible, to render them even more 

 conspicuous ; but amongst the intricate lines and 

 varied colours of foliage and flowers, and if the 

 insect be a little out of focus, the effect is very 

 different. 



2. Let us begin with the Elephant Hawk-moth. 

 The caterpillars (fig. 13), as represented in most 

 entomological works, are of two varieties, most of 



