267 



It is well knowu how Weismann brought back the eye spots 

 and the ringed spots to the linea subdorsalis. He distinguishes foiir 

 ontogeiietic and phylogenetic stages in the course of development 

 üf the ooiourpattern during hxrval life. 



Stage I. Green, without any pattern. 



Stage II. Subdorsal line, sometimes also a dorsal and a stigmal line. 



The biological value of this stripe was that it divided the 

 strikingly large body of the Caterpillar into parts and in that way 

 made it less conspicuous. 



Species showing this longitudinal striation lived on grasses and 

 conifers. 



Stage III. Cross stripes 1. c. p. 127. 



New characters arise only during the ultimate stages of the 

 larval life and when new ones are developed, they disappear from 

 the last stage and arise in the former one. The character of the 

 cross stripes becomes completed by accompanying coloured borders 

 (shadow). 



Stage IV. The eye spots (with a dark pupil = central spot, a 

 bright shining spot and a dark ring) and the ringed spot (without 

 central spot) arise from or in connection with the subdorsal line, 

 on the fourth and fifth segment of Chaerocampa (1. c. p. 97) and 

 on the eleventh caudal-horn segment of Deilej)Jiila. The spotted 

 pattern is a warning colour. Weismann was able to point out a 

 biological meaning for these three principal clements of the sphin- 

 gidal pattern and thus he could explain their origin by natural 

 selection. For the explanation of the repetition of a locally origi- 

 nating pattern on the other segments, however, he had to refer 

 to the rule of correlation (1. c. p. 136). 



Weismann declares positively that the first stage has no 

 pattern e. g. BeiUpJiila e-uphorhiae (1. c, p. 25). „When, however, 

 the youngest larvae of this species are scrutinized with a high 

 power, it is seen that from the beginning they are dark-green, 

 while the horn is black, so also are the head, the feet and a 

 serai-circular chitinous shield on the dorsum of the prothorax and 

 one paired and two unpaired chitinous shields on the last segment. 



