11 



about 15 per cent kerosene or crude petroleum. Results with the 

 pure oils were more quickly apparent, so that these were preferred 

 b}^ the planters. Thousands of grasshoppers were thus destroyed 

 within a few square feet. By a thorough use of these methods, as 

 local circumstances warranted, the planters were able to so reduce the 

 numbers of grasshoppers 

 that they did but little 

 damage after the latter 

 part of April. About 

 this time, also, large 

 flocks of ricebirds and 

 blackbirds appeared and 

 fed on the grasshoppers 

 for several days. Had 

 the outbreak remained 

 unchecked several re- 

 plantings would have 

 been necessary, and a 

 recurrence of the pest 

 the next season would 

 have been probable. 



This outbreak, as well 

 as the previous ones, was 

 undoubtedly due to the 

 large areas of unculti- 

 vated land in the river 

 bottoms in 1903, as a re- 

 sult of the floods of the 

 summer of 1902 and the 

 spring of 1903. These 

 uncultivated fields, grown 

 up to rank weeds which 

 are the favorite food of 

 the grasshoppers and 

 with a hard, baked soil, 

 furnished an ideal place 

 for them to nuiltiply and 

 in which to lay their eggs 

 in the fall of 1903. From 

 these fields and from uncultivated fence rows the yoimg emerged in 

 the spring of 1901, and in many cases it was difiicult to successfully 

 cope with them, owing to the fact that the fields from which they 

 emerged remained uncultivated and in them nothing was done toward 

 checking the pest. 



223 



Flo. G.—MektnoplKS differeniialU on corn leaves: nymph in 

 natural position, upper figure; pupa skin below on right— 

 (original). 



