THOMAS ON ORTHOPTERA OF DAKOTA AND MONTANA. 489 



Now, let US examine briefly the history and characters of their migra- 

 tions in the Mississippi Valley, and see what important facts bearing 

 upon the question of a preventive cau be ascertained, and especially as 

 to the places from which individual hordes which visit this region take 

 their departure. But first I desire to present a few facts in regard to 

 the Eastern locust, (Edipoda migratoria, as indicative of what we may 

 j)robably expect here. The earlier invasions of Europe by this species 

 are always said to be from Arabia or the interior of Asia, as, for ex- 

 ample, the horde which visited Silesia in 1542, the regions around Milan 

 in 1556, and of Marseilles in 1613. But as observations began to be 

 more exact, and the records more perfect, we hear of intermediate sta- 

 tions and less extensive single marches; for example, the invasion of 

 Hungary and Germany in 1693 is said to have been from Thrace, much 

 nearer the scene of their depredations than the locality given former 

 hordes. The great European invasion of 1719-50 was the result of sev- 

 eral steps 5 in 1747-48, it is stated, they came from Turkey into Wal- 

 lachia, Moldavia, Transylvania, and Hungary; from thence, in 1749, 

 they passed into Austria, Bavaria, and other parts of Germany, and 

 from thence, in 1750, reached the Mark of Brandenburg. But beyond 

 Thrace in the one case and Turkey in the other nothing is known of 

 their progress. I am aware that seemingly well attested instances of 

 flight from three to five hundred miles from shore are given ; and also 

 the very common statement of their passage across the Mediterranean; 

 but Hasselquist, and also Zinnani, who lived at Venice, deny the truth 

 of the latter statement; and the leading orthopterologist of Europe was 

 unable to correct them, if wrong, as late as 1853. 



It may, therefore, be possible that when we can trace the swarms 

 which visit Kansas and Nebraska to their hatciiing-grounds, we will 

 find them not so far distant as is now generally supposed. As bearing 

 on this point, I give the following facts and statements, partly from the 

 full records of Mr. Walsh, Professor Eiley, the Agricultural Reports of 

 Kansas, and Agricultural Department at Washington, and from my own 

 knowledge. 



It appears from the Canada Farmer, as quoted in Eiley's Eeport, that 

 in 1857 these insects visited the Assiniboiue settlement in Manitoba. 

 Now, by turning to Mr. Taylor's account of the locusts as given in the 

 Smithsonian Eeport of 1858, we find that they were very destructive to 

 the grass of the Plains that year, from the Upper Missouri to Port 

 Kearney, and migrating. There may be no connection between the 

 two, but subsequently, in 1871 or 1872, swarms appear to have passed 

 up from Dakota to Manitoba, indicating a disposition in this northern 

 section to move northeast. In 1864, we hear again of invasions of Ma- 

 nitoba and Minnesota, and this year the great hatching-ground also 

 appears to have been the Upper Missouri and Yellowstone region. But 

 the great mass this season appears to have spread southeast and east 

 upon the Plains, sending a strong wing down the mountain flank to 

 Bull. iv. No. 2- — 12 



