The Origin of the Markings of Caterpillars. 219 



greyish-green ground-colour, and most of them had 

 exactly the simple marking as represented, for 

 instance, in Hubner's figure, i. e., a rather broad 

 greenish-white subdorsal line, somewhat faded at 

 the edges, and without a trace of spots on any of 

 the segments with the exception of the eleventh, 

 on which there was a yellowish, black-bordered 

 mirror-spot, with a broad, diffused, vivid orange- 

 red nucleus. Specimens also occur, and by no 

 means uncommonly, in which no other markings 

 are to be seen than those mentioned ; there were 

 nine among twenty-eight examples compared from 

 this point of view. 



In many other individuals of this species small 

 red spots appear on the subdorsal line, exactly in 

 the positions where the ring-spots are situated in 

 the other species of the genus (Fig. 60), so that 

 these spots are thus repetitions of the single ring- 

 spot a fact which must appear of the greatest 

 interest in connection with the development of the 

 markings throughout the whole genus. But this 

 is not all, for again in other specimens, these red 

 spots stand on a large yellow " mirror," and in one 

 individual (Fig. 59), they had become developed 

 into well-formed ring-spots through the addition of 

 a black border. We have thus presented to us in 

 one and the same stage of a species, the complete 

 development of ring-spots from a subdorsal line. 

 These facts acquire a still greater interest, as show- 

 ing how new elements of marking are produced. 



