141 



(H)lor appears firet in centres which upon the body are metame- 

 rioally 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 n)und the bases of the setae or in the verrucae, so 

 that the primary pattern oonsists of pigmental spots arranged 

 according to type 1. This {>attern is repeated on each segment 

 and hence has a metamerical chan»cter. 



The strip(>s arise in the ontogeny either simultaneously with 

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



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

 of a stripe and I think I have succeeiled in Phalera hurephuht (see 

 p. C5 sq«|.). In instar / the ordinary pattern (type I) is present. 

 In the cours(> of the development the number of spots increases 

 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 am not quite sure whether 

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

 that the stripes have suddenly arisen, perhaps as mutations. 



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 p|irt of a segment over the whole 

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

 arranged on the segment in a certain pattern. 



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

 because of the strong homoiomery which governs the structure 

 of the body of caterpillars, but a continuous 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. 



