44 



TYPES OF MENDELIAN HEREDITY 



like the age of the individual, also be considered as 

 influences external to the hereditary factors which 

 affect the development of characters. And not only 



4^ 



B 



Qn-'4 



Fig. 20. — Leptinotarsa signaticollis (above), and L.' undecimlineata 

 (below), with their full grown {B) and second stage (C) larvae to the right 

 of each. (After Tower.) 



do regional peculiarities influence characters, but 

 special regions are usually required for a given factor 

 difference to manifest itself, just as certain tempera- 

 tures or ages may be necessary. Thus when we 



