The Origin of the Markings of Caterpillars. 163 



but it soon becomes manifest that such is certainly 

 the case in a great measure. In all species the 

 young caterpillars are differently marked to the 

 adults, and in many the markings change with 

 each of the five stages of growth indicated by the 

 four ecdyses, this gradational transformation of 

 the markings being a " development " in the true 

 sense of the word, i. e., an origination of the com- 

 plex from the simple, the development of characters 

 from those previously in existence, and never an 

 inconstant, unconnected series of per saltum 

 changes. This development of the markings in 

 individuals very well reveals their phyletic de- 

 velopment, since there can be no doubt but that 

 we have here preserved to us in the ontogeny, as 

 I shall establish more fully further on, a very 

 slightly altered picture of the phyletic develop- 

 ment. The latter can have been but slightly 

 " falsified " in these cases, although it is indeed 

 considerably abbreviated, and that in very different 

 degrees ; to the greatest extent in those species 

 which are most advanced in their phyletic de- 

 velopment, and to the least extent in those which 

 are less advanced. From this the value of being 

 able to compare a large number of species with 

 respect to their ontogeny will appear. Unfortu- 

 nately, however, this has only been possible to a 

 very limited extent. \ 



The youngest larval stages are those which 

 are of the most importance for revealing the 



M 2 



