28 



BULLETIN 173, U. S. DEPARTMENT OF AGRICULTURE. 



50.7° F., or about the same as in 1909, and the emergence probably 

 would have been very similar to the emergence for that year but 

 for the abnormal precipitation in February and March, especially 

 in the latter month. 



950 

 900 











































































0SO 







































800 

 750 

 700 

 650 

 €00 























































































































































































550 

 500 

 450 

 400 

 350 

 300 

 250 

 200 

 /50 

 /OO 

 50 

 















































































































































































































































































































































































































































/4 /6 /5 20 22 24- 26 2& 2 4 6 5 /O /2 /4 /6 /8 

 FFBRU^Rr MARCH 



Fig. 9.— Curve showing emergence of adult thrips at laboratory, Walnut Creek, Cal., 1909. 



(Original.) 



Table II. — Mean temperatures for the months of February and March, 1909, 1910, and 



1911. 



"F. 



Mean maximum temperature for month of February, 1909 59. 2 



Mean minimum temperature for month of February, 1909 42. 2 



Average mean temperature for month of February, 1909 51. 



Mean maximum temperature for month of March, 1909 60. 



Mean minimum temperature for month of March, 1909 40. 



Average mean temperature for month of March, 1909 50. 



58.8 



38.5 



Mean maximum temperature for month of February, 1910. 

 Mean minimum temperature for month of February, 1910. 



