INFLUENCE OF CULTURAL CONDITIONS. 



49 



Table IX. — Explanation of variation in temperature effects at Hallettsville and 



Kerrville, Tex. 





Temperature conditions. 



Rainfall a 



nd clo 



id conditions. 





Absolute max- 

 imum. 



Average. 



c 



o 

 be ■ 



> o 



s 



I 



o _; 



P. 



o 



Q 



Rainfall 



Cloudiness. 



Locality. 



Degrees Fah- 

 renheit. 



Number of 

 days occur- 

 ring. 



c 

 3 

 Jj 



6 

 1 



o 





-3 



U 



B ■'■ 

 - -: 



"r £.>. 



art 



z 



. 



u 



•- g 



s. 



5* 



Hallettsville 



Kerrville 



99 

 98 



5 

 2 



°F. 

 95.0 

 95.3 



°F. 

 74.1 



69.5 



°F. 

 84.0 

 82.4 



°F. 

 + 1.1 

 + 1.2 



/TO. 

 0.85 

 3.47 



Inches. 

 -1.54 

 + 1..90 



3 

 9 



c 



14 



11 



13 



14 

 4 



Such differences as those shown in rainfall and cloud conditions 

 are entirely sufficient to explain the difference in the effectiveness of 

 similar maximum temperatures. 



At Cuero the month of June was extremely hot and dry, showing a 

 temperature averaging 4.6 degrees above normal and rainfall 2.04 

 inches below normal. These conditions are probably responsible for 

 the major portion of the crop that was set in that locality. During 

 Jury there was an excess of rainfall amounting to 2.63 inches, while 

 during August the excess amounted to 0.77 inch. While the mean 

 average temperature for August was 1 degree below normal, the 

 mean maximum temperature ranged very high. In this case it 

 appears that the mortality from heat or drying, amounting to 29.5 

 per cent, was due not so much to drought as to the fact that the 

 maximum temperature experienced during the month reached 95 

 degrees or higher upon nineteen days. In this case, apparently, heat 

 may have been the important factor rather than drying. 



At Waco, Junction, and Victoria, Tex., the mortality is very 

 evenly divided between heat and ants, the excess at Waco being due 

 to a much larger percentage of parasitism. At Brownsville a large 

 proportion of the mortality appears to have been due to heat, and 

 this would seem to be a natural condition for that locality. 



The study of the data shown in Tables VII and VIII for the locali- 

 ties in Group B indicates similar conclusions for those shown for 

 Group A. At Mineola, in a total mortality of 51.4, 31.5 per cent was 

 due to heat or drying, and the remarks state that it was "very dry 

 and hot" at the time the collection was made. 



At Trinity, with 50.5 per cent mortality, but 10.4 per cent was due 

 to heat, while the destruction of stages by ants amounted to 37.7 per 

 cent. The remarks show that although a Large portion of the leaves 

 had fallen from the plants because of a fungous disease, the excessive 

 amount of rainfall would naturally prevent a large mortality from 

 heat or drying, while the presence of "many Solenopsis" directly 

 explains the large proportion of the total mortality which was due to 

 11575— Bui. 74—07 4 



