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. 



/ooo 



950 

 900 



eso 



SOO 

 750 

 700 

 650 

 €00 

 S50 

 SOO 

 450 

 400 

 350 

 300 

 250 

 200 

 /SO 

 /OO 

 SO 

 O 



Fig. 9.— Curve showing emergence of adult thrips at laboratory, Walnut Creek, Cal., 19 



(Original.) 



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



1911. 



Mean maximum temperature for month of February, 1909 



Mean minimum temperature for month of February, 1909 



Average mean temperature for month of February, 1909 



Mean maximum tempera ture for month of March, 1909 



Mean minim um temperature for month of March, 1909 



Average mean temperature for month of March, 1909 ■ 





































- 





































































































































































































































































































































































































































































































































































































































































































/4 /€ /a 20 22 24 2G 2a 2 4 6 a /O /2 /4 /€ /a 

 FEBRU^RV MARCH 



and. 



°F. 

 59.2 

 42.2 

 51.0 

 60.0 

 40.0 

 50.0 



Mean maximum temperature for month of February, 1910. 

 Mean minimum temperature for month of February, 1910. 



