230 Heredity and Eugenies 



has been absorbed by miiltitacniata, but not completely 

 incorporated — traces of it occurring in every generation 

 with greater or less frequency. Both the mdaiiothorax 

 and miiltitacniata develop among the progeny of the same 

 parents, and bet\Yeen them there is a striking difference in 

 the development of the pattern. Both start from essen- 

 tially the same base, but i)iclaiwtliorax diverges with great 

 rapidity and does not pass through the stages of the parents 

 from which it came, as sho^\^l in Fig. 75. 



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

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

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

 having very little in common with L. vuillilaoiiala from which it came. This 

 suggests that this t5'pe of development is as much a si>ecihc and independent 

 character as is its final form. 



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

 of mclanothorax Avere observed for several generations, 

 injections of dilute solutions of calcium nitrate caused it 

 to gi\'e viclanotliorax. 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 viclanotliorax 

 represents another t}j>e of pattern modification — a rapid 

 di\-ergence from the initial state common to a very wide 

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



