MONTANA EXPERIMENT STATION. 217 



time, we have observed a similar, thouj^h less extensive, early hatch- 

 ing and killing of the lice. 



If not destroyed by natural enemies or climatic conditions, the 

 3'oung lice in due time become mature and begin to produce young. 

 Dr. Smith of New Jersey* found that about fifteen days were requir- 

 ed for the first generation to reach maturity after hatching. The lice 

 are known as the "Stem mothers," (See Fig. 4, b). They are wing- 

 less and are greenish in color. No males are produced from the eggs 

 and the stem mothers are able to produce young without them. 



The young of the second generation (offspring of the stem moth- 

 ers) are produced alive — not hatched from eggs — and are able to 

 begin feeding almost immediately. Tlrey settle down near the moth- 

 er and one may often find a stem mother with her large family close 

 by her. Our office notes show that the stem mother gives birth to 

 young at the rate of from one to fourteen per day, and that she con- 

 tinues day after ilay for fully eighteen days, producing an average 



Figure 6, Male of the oviparous 

 generation greatly enlarged. (Sander- 

 son 14th Ann. Kept. X. J. Exp. 

 Station. 



number of about six or seven. Thus each stem mother produces 

 fully lOO young, 



*Bulletin 143 of the N. J. Experiment Station. 



