SCALES IN MINNESOTA. 463 
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FiG. 2.—Colony of Cochineal insect on a cactus. 
grown the males appear, and soon afterwards eggs are laid for the 
next generation. About six weeks are required to complete the 
cycle of life; hence, we can have many generations in-the course of 
a year, especially if the greenhouses are kept uniformly warm. 
The Cottony Maple-scale (Pulvinaria innumerabilis. RATH) 
During the first half of the summer many trees, but most frequently 
the box elders and maples, are infested with this scale, and small 
tufts of a white cottony matter can be seen upon their branches. 
This material, when touched, is found to be sticky, and can be 
Fic. 3.—Cottony Maple-scale. 
drawn outin fine threads. It is acover for the eggs of this insect. 
The illustration, figure three, shows a number of such scales with 
