April, '15] 



NEWELL: SUDAN GRASS INSECTS 



231 



of the distribution and abundance of the insect. The following table 

 shows the location of these stations, the annual rainfall and the esti- 

 mated damage to the Sudan seed crop during the past two seasons : 



Raiotall and Injury to Sudan Grass Seed 



Station 



Average 

 Annual Rainfall 



Estimated Damage to Seed Crop, 

 Sudan Grass 



Length of 

 Record, Years 



■Inches 



1913 



1914 



Angleton 



IS 



AQ 



lUU/o 



90 /o^ 







7 





DU/o 



iUU /o 







g 



A'i 7Q 



■±0 . /y 



iUU/o 



lUU /o 







Beaumont 



20 



42.654 



20% 



100% 







24 



37.874 



40% 



95%2 





Chillicothe 



8 



33.64 



None 



None 







Temple ." 



28 



33. 36* 



None 



50% 







1 



33.14 



15% 



50% 





Beeville 



18 



30.054 



None 



50% 





Lubbock 





21.74 



None 



None 







Spur 



3- 



18.40 



None 



None 







4 



7.93 



None 



Non? 







1 U. S. Weather Bureau record at Alvin, 20 miles from Angleton. 



* A small seed crop produced very late in the season. 



2 U. S. Weather Bureau record at Lufkin, 15 miles from Nacogdoches. 



* U. S. Weather Bureau record. 



This table shows that localities having an average annual rainfall 

 of 35 inches or more have experienced almost total destruction of the 

 seed crop for the past two years, whereas localities with an average 

 rainfall of about 25 inches or less have been exempt from damage. 

 Between these two extremes, i. e., in localities where the average rain- 

 fall is between 25 and 35 inches, the amount of damage has been highly 

 variable. 



Sufficient data are not yet at hand to permit of any positive correla- 

 tion between local cUmatic conditions and the extent of midge injury. 

 However, it appears in general that, the greater the precipitation 

 during the spring and early summer months, the greater is the damage 

 by the midge. This is indicated by the data following: 



