68 



THE MONTHLY BULLETIN. 



Just before the apple buds show green the eggs begin to hatch. This, 

 of eonrse, depends entirely npon the weather, and an early spring 

 will bring a much more rapid development than will a cold, late 

 spring. 



Stem Mothers. — The young which hatch from the eggs in the early 

 spring give rise to all succeeding generations, and are known as "stem 

 mothers" when fully developed. The first young are darker green 

 than any of the succeeding broods. In seeking food they work into the 

 newly opening buds and on the first tender leaves. Due to their small 



size they can scarcely be noticed except by very 

 careful observation. They seek the young buds 

 for two reasons : first, because the tender leaves 

 furnish the first food; second, because hid down 

 in the folds of the luids they are free from the 

 attacks of natural enemies, and incidentally out 

 of reach of sprays. In warm weather the young 

 will develop in two or three weeks and become 

 adult stem mothers. These stem mothers still 

 appear dark green and have a distinct, dark 

 head, feet, tail and honey tubes. They do not 

 have wings, a characteristic of this brood. 



Second Generation. — Every stem mother 

 when full grown has the power (which we call 

 parthenogenesis) to give birth to living young 

 without intercourse with a male, for no males 

 appear at all until late in the fall. The young 

 thus born alive constitute the second generation. 

 They are light green in color, are all partheno- 

 genetic females, and though most of them are 

 wingless, a very few winged individuals appear, 

 Imt these like the apterous forms are females. 

 mgam^ Third Generation. — The new broods of the 



Ir'JL'^ffi ;^^i W I second generation develop in a few weeks and 



in turn give birth to living young like them- 

 selves, but this generation is accompanied by a 

 large number of winged females. The apterous 

 and winged females of the succeeding genera- 

 tions are those most usually observed in the orchards and cause the 

 great(^st amount of damage. A brief descriptions of each is as follows : 

 Wingless Female.— This form is somewhat larger than the original 

 stem mother, and is lighter green in color, with a yellowish tinge. The 

 cornicles (honev tubes), tail, part of the antenUcT and the extreme tips 

 of the feet are dark. This form has the power to give birth to both 

 living wingless and winged lice. 



Winged Female.— These are recognized at once by their wings, 

 which are usually folded roof-like over the back. The general color 

 is black and green (the head, thorax, cornicles and portions of the 



Fig. 55. — Eggs of 

 the green apple aphis 

 (Aphis pomi DeGeer ) 

 on young apple twig. 

 (Original.) 



