THE OUTBREAK OF 1903. 



25 



being complete. The same gentlemen reported the pest present in 

 limited numbers during the spring of 1904 in Collin, Hunt, and 



Diagram III. — Map of the United States east of the Rocky Mountains, showing normal temperature, 

 upper line, and departure therefrom, lower line (+, above normal, and — , below), for the critical period 

 December, 1900, to May, 1901; above normal ( + ) in winter and below normal (— ) in spring being 

 favorable for outbreak of spring grain-aphis. (Original.) 



Travis counties. This year, however, the parasites evidently did 

 more effective service, as at Whitewright, Grayson County, Tex., on 

 March 10, 1904, Mr. Sanborn found that 60 per cent of the Toxoptera 



