230 



Heredity and Eugenics 



has been absorbed by multitaeniata, but not completely 

 incorporated — traces of it occurring in every generation 

 with greater or less frequency. Both the melanothorax 

 and multitaeniata develop among the progeny of the same 

 parents, and between them there is a striking difference in 

 the development of the pattern. Both start from essen- 

 tially the same base, but melanothorax diverges with great 

 rapidity and does not pass through the stages of the parents 

 from which it came, as shown in Fig. 75. 



Fig. 75. — ^To show the sequence of stages in ontogeny in L. multitaeniata (A) 

 and its recurrent mutant, melanothorax (B). It should be noted that the latter 

 form has its own type of development and diverges from the parental condition, 

 having ver>' little in common with L. multitaeniata from which it came. This 

 suggests that this type of development is as much a specific and independent 

 character as is its final form. 



In a pure strain of L. multitaeniata Stal, where no traces 

 of melanothorax were observed for several generations, 

 injections of dilute solutions of calcium nitrate caused it 

 to give melanothorax. In these induced forms the ontogeny 

 of the color, pattern is the same as in the development of 

 material found in nature. This behavior of melanothorax 

 represents another type of pattern modification — a rapid 

 divergence from the initial state common to a very wide 

 range of species, and in no wise is it a repetition of the 



