THE PEAE THRIPS IN CALIFORNIA. 



31 



Table III. — Total 'precipitation for the years 1909, 1910, and 1911 at San Jose, Cal., 



laboratory. 



Month. 



Precipitation in inches. 



1909 



1910 



1911 





4.87 

 2.77 



0.83 

 2.84 



2.03 

 . 6.26 







One curious fact about the emergence for 1911 was the double 

 maximum, one the latter part of February, from the 18th to the 26th, 

 and another from the 8th to the 15th of March. (See Table IV and 



4400 

 4200 

 4000 

 3800 

 3600 

 3400 

 3200 

 3000 

 2800 

 2600 

 2400 



2000 

 /80O 



MOO 

 /200 

 lOOO 

 800 

 600 

 400 

 200 



Fig. 13.— Curve showing emergence of pear thrips at San Jose, Cal., 1910. (Original.) 



fig. 14.) From February 26 to March 11, inclusive, it rained every 

 day from 0.02 of an inch to as much as 2.45 inches. Probably a 

 number of the thrips which emerged in February were killed by the 

 heavy rains in early March, or at least were not permitted to cause 

 much injury. The pear thrips emerges from the ground during rainy 

 weather, but not in such great numbers as during warm, sunshiny 

 days, which was the case during the latter part of February and the 

 early part of March of the year 1910. Whether the soil is clean or 

 covered with weeds and grass at this time of year influences the time 



























































































































































































































it 





































































































































































































































































































































































































































































1 



















































V 





















































































































































































































































































































































































/O /2 A7 /S /8 20 22 24 26 28 2 & 6 8 /O /2 14 /6 /8 20 22 24 26 28 

 FEBRUARY 1 MARCH 



