10 STATISTICAL METHODS. 



ant may then be compared with the color wheel. By this 

 means also the total melanism or albinism, viridescence, etc., 

 may be measured. 



Marking-characters. The quantitative expression of 

 markings or color patterns will often call for the greatest 

 ingenuity of the naturalist. Only the most general rules can 

 here be laid down. Study the markings comparatively in a 

 large number of the individuals, reduce the pattern to its 

 simplest elements, and find the law of the qualitative variation 

 of these elements. The variation of the elements can usually 

 be treated under one of the preceding categories. Find in how 

 far the variation of the color pattern is due to the variation of 

 some number or other magnitude, and express the variation in 

 terms of that magnitude. Remember that it is rarely a ques- 

 tion whether the variation of the character can be expressed 

 quantitatively but rather what is the best method of express- 

 ing it quantitatively. 



