44 INHERITANCE IN SILKWORMS, I 



only subsidiary interest. It is a variation or character strongly subject 

 to Galton's law of regression and does not seem to be capable of any 

 considerable modification or degree of fixation by even a most careful 

 and persistent personal selection. 



The pattern consists of the presence, in more or less well-marked 

 condition, of a number of dark curving lines or bars crossing the white 

 or creamy wings from anterior to posterior margin. These lines may 

 be broad and strongly blackish, or narrower and only smoky, or very 

 narrow and faint, or nearly invisible. All gradations from almost total 

 absence of this pattern, when the wing may be called white (W), up 

 to the most marked and elaborate condition of the pattern, when the 

 wing may be called strongly patterned (S. P.) are to be noted. (See 

 figures I to 3, Plate II.) For convenience I have established four 

 arbitrary categories or pattern classes, which I call respectively White 

 (W.), Barely Patterned (B. P.), Medium Patterned (M. P.), Strongly 

 Patterned (S. P.). As examples of the manner of inheritance of this 

 variation a short series of lots from the 1906 rearings (from the total 

 series of nearly 300 in which pattern differences were tabulated) may 

 be referred to. The small number of moths representing each lot is 

 due to the fact that not all the cocoons were allowed to give up their 

 moths and that from many that did the moths were allowed to make 

 their condition of pattern undecipherable (by much beating of wings 

 in the small mating boxes) before they were examined for tabulation as 

 to wing-pattern. The records however show plainly the fluctuating 

 and continuous character of the variation, even if the numerical repre- 

 sentations of the dififerent pattern types are not capable of being 

 construed as indicating the actual proportions in any whole lot. 



(Lot M. 22.) S. P. male mated with W. female. Result, 12 M. P., 

 5 S. P. and 6 melanic. (Note; male parent was a medium melanic.) 



(Lot M. 44.) S. P. male mated with W. female. Result, 7 W., 

 20 B. P., II M. P. 



(Lot M. 13.) S. P. male mated with B. P. female. Result, 17 

 B. P,. 5 M. P. 



(Lot M. 12.) M. P. male (cream color) mated with M. P. female. 

 Result, 4 W., 13 B. P., 12 M. P., i S. P. 



(Lot M. 41.) B. P. male mated with S. P. female. Result, i W., 

 3 B. P., 5 M. P., 15 S. P. 



(Lot M. 29.) S. P. male mated with B. P. female. Result, 4 

 B. P., 13 M. P., 3 S. P. 



