180 



THE EVOLUTION THEORY 



When we consider that this stripe in the httle caterpillar 

 a centimetre long, which lives on the large leaves of the vine, or on 

 the obliquely ribbed willow-herb (E2)ilohmm hirsutum), is quite 

 without protective value, its occurrence at that stage can only be 

 regarded as a phyletic reminiscence due to the fact that the ancestors 

 of these species of GhcBrocmnpa possessed longitudinal stripes in 

 the adult state, probably because at that time they lived on plants 

 among the grass, and that, later, when the species changed their 



Fig. ii6. Development of the eye-spots in the caterpillar of the Elephant 

 Hawk-moth {Chcerocampa elpenor). A, Stage I, still without niai'king, simply 

 green. B, Stage II, with sub-dorsal stripe (shd). C, sub-dorsal line somewliat 

 later, with the first hint of the eye-spot (An) on segments 4 and 5. D, eye- 

 spots in Stage III of the caterpillar, somewhat further developed than in E, 

 F, Stage IV. G, the anterior eye-spot at the same stage. 



the third stage 



habitat to plants with broad leaves which had arisen in the meantime, 

 ej'e-spots were developed in addition to the green or brown protective 

 colouring which they retained. Thus the modern development of 

 these spots mirrors their phyletic evolution very faithfully ; on the 

 two segments there were formed, from pieces of the sub-dorsal line, 

 first white spots ringed round with black, then unmistakeable eyes 

 with pupils (C, JD, G). This transformation can only have begun in 

 the fairly well-grown caterpillar, because it was only of any use to it ; 

 but later on it was shunted further back in the ontogeny, from the 



