216 



MONTANA EXPERIMENT STATION. 



DESCRIPTION AND LIFE HISTORY. 



Like many other plant lice, the apple-aphis passes the winter in 

 the egg state. In the spring the eggs hatch, producing very minute, 

 dark greenish lice which may be found crawling about over the sur- 

 face of the bark or closely nestled on the young buds and expanding 

 leaves. 



The spring of 1902 was looked upon as being very cold and back- 

 ward in the Gallatin valley, and the writer was much surprised in 

 going into the Station orchard on April i6th to find an abundance of 

 newly hatched lice. The buds had not started and were no more 

 swollen than they were the fall before. There had been a few days 

 of hot weather which had caused the lice to hatch, but had not been 

 of long enough duration to start the buds. Part of the lice had been 

 feeding and had distinctly increased in size. 



On April 19 a cold storm came and on the 20th there were about 

 three inches of snow. For the next few days the writer was out of 

 town, but on May i the trees were examined and the lice were found 

 to have been nearly all killed. Only two living ones could be found 

 and many dead bodies were still attached to the twigs. Since that 



Figure 5. Winged viviparous female gi-eatly enlarged. (Sanderson, 13tli Ann. Rept. N. J. 

 Exp, Station. 



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