WINDS AND MEAN TEMPERATURE FROM 1872 TO 1877. 201 

 Synopsis of the viontlily mean temperature and ivinds in the locust area, ^c. — Continued. 





September. 





1872. 



1873. 



1874. 



1875. 



1876. 



1877. 



Station. 



1 



1 

 B 



<s 





6 



u 



a 



a 



- P 



B 

 S 





6 



(-1 



i 



i 

 ^ 



1 



s 



a 



a 



S 



2 

 K 

 a 









64.6 



SW 



62.3 



SW 



65.5 



SW 



61.7 



55.1 



55.4 



56 



61.7 



68.7 



SW 



NW 



NW 



NW 



S 



s 







67.3 



60.5 



58 5 



.56.2 



61.9 



68.4 



70.5 



64.7 



70.1 



67.9 



64.6 



66.6 



64 



61.4 



64.7 



SW 



Bismarck Dali 







w 



Breckenr'd'fe Minn 



58.3 

 55.6 

 60.1 



SE 

 NAY 



S 



49.1 

 55.9 

 59.8 



'76.' 2' 

 57.3 

 65.4 

 63.9 



NW 



"s" 



" se' 



-NW 



s 



NW 



57.7 

 54.2 

 59 



'ii'.h' 



65.2 

 66.8 

 67.1 



s 

 w 



s 



■ se" 



SE 

 S 



s 







s 









w 



Denver Colo 



SE 



Dodge City, Kans 



jFort Gibson Ind T 







S 

 SE 



Fort Sully, Dak 



62.4 

 67.7 

 63.2 



NW 



SW 



S 



61.3 

 66. 6 

 64.3 

 62.5 

 62.9 

 57.2 

 53.7 

 60.6 

 60.6 

 52.7 

 68.8 



S 



S 

 SE 



S 



SE 

 SW 



w 



WW 



NE 







SE 



T^^polfnk Town 







s 



Leavenworth, Kans 



North Platte, Nebr 







S 

 NE 



Omaha Nebr 



62.8 

 57.6 

 60 



55." i' 



SE 



■ se' 

 "sw 



60.6 



54.1 



61 



60 



53.2 



4G.8 



S 

 SW 



w 



NW 



63 



60.9 



CO. 5 



61.7 



58.2 



56.2 



62.6 



s 



SE 



E 

 NW 

 SW 



NW 



NW 







s 



Saint Paul, Minn 







.... 



SE 



Santa Fe, N. Mex 



SE 



Yankton Dak 







s 



FortBentrn Mont 









Pembina Dak 



51.9 

 65.6 



NW 



NW 



55.4 

 65 

 61 

 68.3 



s 



Salt Lake City 







NW 



Boise City 











s 





















76 



S 



S 



Colorado Springs 











56.7 



SE 



57.9 



N 





















The following thoughts on the subject are taken, with some omissions 

 and alterations, from Mr. Packard's Eeport to Dr. Hay den. ^^ 



We have shown that the exceptional years when the locust migrates 

 are periods of unusual heat and dryness, conditions unusually favor- 

 able to the excessive increase of insect life, as is the case with the 

 Eastern and California locust, the grass army-worm, the grain-aphis, 

 and the chiuch-bug. When the early part of the season, the spring and 

 early weeks of summer, are warm and dry, without sudden changes of 

 temperature, insects abound, and enormously exceed their ordinary num- 

 bers. When two such seasons occur, one after the other, the conditions 

 become still more favorable for the undue development of insect life. It 

 is well known that in the Eastern States the summers of 1860 and 1874 

 preceding the appearance of the army- worm and grain-aphis, were un- 

 usually warm and dry, and favorable not only for the hatching of the 

 eggs laid the year previous, but for the growth and development of the 

 larvae or young. Look now at the conditions for the development of 

 locust life on the hot and dry plains — Montana, Wyoming, and Utah. 

 We have no extended meteorological records from these regions at hand, 

 but from the data we have given it is more than probable that the years 

 preceding the migrations of the locusts were exceptionally warm and 

 dry, when the soil was parched with long-sustained droughts, as we 



2s Report on the Rocky Mountain Locust and other Insects, etc. 

 for 1876, 1877, pp. 640-647. 



3th Ann. Rep. U. S. Geol. Surv. Ter. 



