16 
cept where, as in some parts of the Pacific coast, the summers are pro- 
longed and equable. 
Commercially cocoons are classed as yellow, white, and green, but 
through the intermingling of races these colors have become merged 
one into the other, and it is often difficult to define the line of demarka- 
tion. The same trouble exists in classifying varieties by the different 
countries or provinces from which they have originally come. Prior to 
the Silk-worm plague of twenty years ago in Europe there was a cer- 
tain degree of exactness in the lines drawn between such races. Then, 
however, the indigenous races were to a large extent blotted out, and 
the egg merchants went first to Turkey, then to Asia Minor and Syria, 
and finally to China and Japan, in search of eggs that should be free 
from “the malady.” Thus it was that there were brought into France 
and Italy a large number of races foreign to those countries. These 
were crossed together, and after the researches of Pasteur had made 
the resuscitation of the native races possible, they were crossed with 
these as well. Thus the identity of the old varieties was, in many cases,, 
lost, or they obtained different names. 
