412 THE CANADIAN NATURALIST. [Vol. viii. 



scattered. These appear to have been specially numerous in the 

 valley of the South Saskatchewan, as it is reported to have been 

 owing to the destruction of the grass by the locusts that the 

 northern herd of buffalo was forced so much further east than 

 usual in 1876. True to their instincts, the broods, on arriving 

 at maturity, flew southward and south-eastward, forming with 

 additions from south-western Manitoba, and parts of Colorado, 

 Wyoming and Dakota, the great army which overspread the 

 Western States. 



In the summer of 1876, the cultivated lands of Manitoba were 

 threatened with locust invasions from two quarters, from both of 

 which dangers they, however, fortunately escaped. The great 

 hordes produced in the north-west might have overspread and 

 devastated the province, as they have formerly done on several 

 occasions. These, however, swept past by its western boundary 

 and going southward, arriving in many of the south-western 

 states too late to do much damage ; whereas, had they visited 

 Manitoba the loss would have been very great, owing to the less 

 advanced condition of the crops. In south-western Minnesota 

 locusts have bred annually since 1873, according to the reports 

 of Mr. A. Whitman and Dr. Riley. In 1876 considerable swarms 

 were produced, and these, on reaching maturity, set out on a 

 migration to the north and north-westward, and might well have 

 reached Manitoba. The determination of the locusts to move in 

 this direction was evidenced (as has often before been noticed) 

 by their waiting for favourable winds. They were, however, con- 

 tinually repulsed, and eventually borne back by the winds to their 

 hatching places, and thence south and south-west to Iowa and 

 Nebraska. 



In an interesting article by Dr. Riley on the " Rocky Mountain 

 Locust," in part reprinted in the last number of the Naturalist, 

 I am glad to see that the preservation of the dry prairie grass in 

 autumn and its firing, for the purpose of destroying the young 

 insects in their breeding grounds in the far west, is warmly ad- 

 vocated. This was suggested in my notes on the invasion of 1874, 

 and may yet, I believe, be carried out with good result. 



Dr. Riley, in his valuable work on the Locust,* is in error 

 with regard to the northern range of the insect, as represented in 

 his coloured maps, especially that facing the title page ; where 



* The Locust or Grasshopper Plague, Chicago, 1877. 



