16 CROP PEST COMMISSION OF 



reaching maturity, and after having been fertilized, the female 

 commences giving birth to living young and continues bringing 

 forth living young for a period (in summer) of about six weeks. 

 Observations made by the writer in Southern Georgia indicate 

 that in the southernmost parts of the United States, young may 

 be produced at almost any time during the winter, during a con- 

 tinued warm spell, the females suspending operations whenever 

 a cold snap makes its appearance. At Moultrie, Ga,, Prof. W. M. 

 Scott found active larvae during twelve months in the year, and 

 as there is considerable territory in Louisiana that is south of 

 the latitude of Moultrie it would not be at all surprising to learn 

 that the insect breeds during the entire year in the lower Missis- 

 sippi Valley, or in those sections south of New Orleans. 



During the productive period of six weeks or over, the fe- 

 male insect gives birth to from 150 to 500 young and as these 

 commence their development soon after birth, it is readily seen 

 that in a short time individuals of all ages are found upon in- 

 fested trees. As a result it is impossible by mid-summer to 

 distinguish one generation from another. Dr. Howard found 

 that in the latitude of Washington, D. C., there were at least 

 four generations per year and perhaps a partial fifth genera- 

 tion. As far South as Louisiana there seems little doubt but that 

 there are at least six full generations during the year and pos- 

 sibly more. 



When one considers the rapidity with which these insects 

 reach maturity and the enormous number of young produced 

 by a single female, some idea of their capacity for destruction 

 is obtained. Dr. Howard has estimated, conservatively, that 

 the progeny of a single pair may, in the course of a single season, 

 amount to the enormous number of 3.216,080,400.* 



Means of Dissemination. 



Dissemination may well be considered under two heads, dis- 

 semination locally from tree to tree and from orchard to or- 

 chard, and dissemination over long distances, as from one lo- 

 cality to another. 



*Bulletin No. 3, n. ser., Div. of Entomology. 



