401 



('ülor appoars first in centres wliioli upon the body are metame- 

 i'ically repeated spots." 



These writers, however, belong to the few who do not consider 

 the stripes to be the most primitive element of the pattern. 



From my investigation it appears to me that the pigment first 

 accumulates round the bases of the setae or in the verrucae, so 

 that the primary pattern consists of pigmental spots arranged 

 according to type I. ïhis pattern is repeated on each segment 

 and hence has a metamerical character. 



The stripes arise in the ontogeny either simultaneously with 

 or later than these spots and are therefore a new characteristic. 



I have tried to find a form in which I could tracé the development 

 of a stripe and I think I have sneceeded in PJialera hiiccpltaJa (soc 

 p. G5 sqq.). In instar / the ordinary pattern (type I) is present. 

 In the course of the development the number of spots inereases 

 a great deal whilst the original pattern gets less distinct. The 

 secondary spots are situated in vertical rows but by a consolida- 

 tion of some primary and secondary spots a horizontal stripe 

 arises. This stripe, however, is less sharply confined than is usu- 

 ally the case on caterpillars, so that I ani not quite sure whether 

 all the stripes are developed in the same way. It may also be 

 that the stripes have siiddenly arisen, perhaps as mntations. 



It is however a fact, that the pigment spots arranged like 

 type I, form a phylogenetic element of the pattern which is 

 older than a stripe. 



Under Eimer's influence we have entirely forgotten that a stripe, 

 i. e. an alteration of a certain part of a segment over the whole 

 breadth, is altogether a different thing froin the series of spots 

 arranged on the segment in a certain pattern. 



A group of spots like this, will be repeated on all the segments, 

 because of the strong homoiomery which governs the structure 

 of the body of caterpillars, bnt a continvious stripe is quite an 

 other thing, for it is an alteration of a certain part of the skin 

 over the total breadth of the segment. 



Such an alteration does not happen on the other organs either. 



