The above statement of conditions is given in order to emphasize 
the importance of a study of the conditions of insect outbreaks. 
Were we better acquainted with accurate environments preventive 
measures would invariably take the place of the more expensive reme- 
dial ones. 
Capt. Charles L. Potter, Corps of Engineers, Memphis, Tenn., has 
kindly furnished the following list of the breaks occuring in the Mis- 
sissippl River (between Roiling Fork and Coahoma, the grasshopper 
infested territory) since 1887: ; 
Distance | 
| by river | 
Name of crevasse. ern Date. | ; Remarks. 
Cairo. 
Miles | 
ORME AS2: SSR" Se 444 | Mar. 18, 1890 | 
Skipwitit..--# tee o 530 | Mar. 26,1890 
Mound Landing...-.-.-. 435 | Mar. 28, 1890 
Huntimeton) 22 oes se.- 438 | Mar. 28, 1890 
Austins: s5 0.5 037) 288 | Apr. 3,1890 | About 30 miles above Coahoma. 
Cathsh Pomte ee! see 432 | Apr. 4, 1890 | 
Robertsonyille ........ 354 | Mar. 11,1891 
Stellates. =. ocbe oss eee 503 | Apr. 3,1891 
Deerheld x2 2k 7. ose 492 | Mar. 28, 1897 
DledPer cess: Teck se%c8 380 | Mar. 30, 1897 
Stop Landing.......... 434 | Mar. 30,1897 
Flower Lake .........- 300 | Apr. 4,1897 | About 20 miles above Coahoma. 
SSH LAM Cuan eet 548 | Apr. 21,1897 | Latitude 8’=about 10 miles south of Rolling Fork. 
There were no crevasses in the Mississippi levees from 1887 to 1890. 
A small crevasse occurred at Greenville in 1891 that was closed before the discharge was appre- 
ciable. 
All the breaks except those at Flower Lake, Austim, and Shipland are located between Coahoma 
and Rolling Fork. 
Grasshopper outbreaks occurred in 1891 and 1892, and again in 
1898, 1899, and 1900. It is a significant fact that the rainfall of May 
and June, 1893, and of the same months in 1900 had a decided effect 
in suppressing the injurious numbers of grasshoppers, and conversely, 
the dry summers immediately following the crevasses encouraged 
greatly their development. 
The following table of rainfall for Greenville, Miss., the nearest 
meteorological station, furnished by Mr. W. 8S. Belden, acting station 
director, Vicksburg, Miss., supports the above conclusions. 
Rainfall at Greenville, Miss., 1888-1900. 
Year. | Jan. | Feb. | Mar, Apr. |May.|June. July.; Aug.| Sept.} Oct. | Nov. | Dec. | Annual. 
| 
WBSS 2): Si. chides tes | 6.11 | 2.41 | 9.88 | 1.65 | 4.54 | 3.95 | 2.28 |10.39 | 2.69 | 1.61 | 3.89 | 3.89 53. 29 
DSBs Ste aa eens. | 4.89 | 2.71 | 1.85 | 2.60 | 4.03 | 7.09 | 4.50 | 1.86 | 4.05 | 0.40 | 5.92 | 1.05 40. 95 
Ce ee aan 4.98 | 6.30 | 6.63 |11.01 | 4.67 | 2.31 | 2.23 | 2.09 | 4.94 | 2.79 | 1.48 | 3.94 53.37 
1891...........--.] 3.79 | 8.38 | 4.43 | 2.24 | 3.42 | 3.02 |12.32 | 2.44 | 1.64 | 0.86 | 5.40 | 3.40 51. 24 
1h) Re a ee cee 5.59 | 8.60 | 3.91 | 9.74 | 2.93 | 2.54 | 9.25 | 3.50 | 6.96 | 0.80 | 2.44 | 6.54 57. 80 
LB ec cin cto xi te oe 1.63 | 5.27 | 2.70 | 5.69 | 7.89 | 6.59 | 2.33 | 2.87 | 2.67 | 0.34 | 6.34 | 1.87 48. 69 
PSA ss dd < eset 7.37 | 8.19 | 9.48 | 4.48 | 0.61 | 0.30 | 5.09 |...... | 1.17 | 1.53 | 0.35 | 4.25 37.81 
USOD Nera s's, dese tak 6.82, |) bs 240 |s002-. 1.71 | 1.32 |11.50 | 4.30 | 7.23 | 0.87 | 1.20 | 3.78 | 3.58 45, 55 
IBOG se se 2, ess iS 3.29 | 5.24 | 7.98 | 2.48 | 1.09 | 0.71 | 0.85 | 1.84 | 0.74 | 3.20 | 4.73 | 0.17 32, 32 
1897... 4.31 | 4.05 111.48 | 1.96 | 2.19 | 105 | 3.85. | 2.24 + T. 2020 | 259618537 44. 66 
LBB Sten -tae cetts aie 8.19 | 2.89 | 2.94 | 3.83 | 3.15 | 2.54 | 1.57 | 7.51 | 6.12 | 5.85 | 4.60 | 1.51 50.70 
O09 es teen esee 9.30 | 4.57 | 5.21 | 2.19 | 4.67 | 1.51 | 2.10 | 0.87 | 1.18 | 1.15 | 0.94 | 4.23 33. 92 
11,1 setews igee eeee 1.94 | 5.44 | 5.64 | 7.11 | 4.02 | 9.29 | 6.11 | 0.93.) 2.58 | 6.03 |----../--.--- 142.98 
| | | 
1 For 10 months. 
