RETURN MIGRATIONS PRIOR TO 1S77. 161 



Serious incursioDS into Iowa from tlie States south begon to be made 

 about the 10th of June, and lasted from that date till about the middle 

 of July. The western counties of the State sutiered considerably from 

 the swarms that were almost constantly passing over, many of which 

 alighted. 



Minnesota was also Invaded by swarms from Nebraska, Kansas, and 

 Missouri, which deposited their eggs in this State. The swarms take 

 various directions, but still many of them leave the State, passing into 

 Dakota and toward the Northwest. Mr. Whitman remarks in his report 

 as follows on the return migration in Minnesota and the Northwest: 



Whether or not it is a general rale that tlie locusts on acquiring wings seek the di- 

 rection from which their parents had come in the preceding year (a rule which the ex- 

 perience of Minnesota fails to substantiate), it is certain at least that in 1S75 •' the main 

 direction taken by the insects that rose from the Lower Missouri Valley country wH.fi 

 northwesterly." (Riley's Eighth Annual Report, p. 105.) These swarms were traced 

 by Professor Riley, moving northerly from the end of May through June and into July, 

 and passing various points in Dakota, Wyoming, and Montana. 



They passed northward over Bismarck at various times between June 6 and July 15. 

 (Same Report, p. 86.) But a still more definite statement as to the final destination oi 

 these northward-moving swarms is found in an editorial of the Winnipeg Standard, of 

 August 19, 1576, entitled " Locust flights." It is there stated that in 1875 '' the locusts- 

 which hatched in Missouri, Kansas, and Nebraska, in an area of 250 miles from east to- 

 -west, and .300 miles from north to south, took flight in June, and invariably went north- 

 west, and fell in innumerable swarms upon the regions of British America, adjoining 

 Forts Felly, Carlton, and Ellice, covering an area as large as that; they vacated on the 

 Missouri River. They were re-enforced by the retiring column from Manitoba, and it 

 Beemed to be hoping against hope that the new swarms of 1876 would not again descend, 

 upon the settlements in the Red River Valley. Intelligence was received here that the 

 insects took flight from the vicinity of Fort Felly on the 10th of July, and then fol- 

 lowed a fortnight of intense suspense." 



There is, of course, in all this a failure to connect by any direct chaia 

 of continued observations the swarms that left the Mississippi Valley in 

 1875 and those which finally disappeared in the region of the mountains 

 and in British America ; still less is it shown that those swarms were 

 the parents of those which are known to have hatched in the same regions. 

 in 1876, or even that those which are known to have hatched there were 

 those which descended upon the lower country in July and August. But 

 there is, at least, a strong series of probabilities. 



In Dakota locusts which flew from the States to the southeast arrived 

 about the 28th of June, and passed on in a northwest course. On the^ 

 same date vast swarms passed over Yankton, going in a northwesterly 

 direction; light clouds passed over Sully, Fort Eandall, and Springfield,, 

 in the same direction and on the same date. At Bismarck locusts ar- 

 rived from a general southerly direction, and by July 15 had all disap, 

 peared, "moving north and west." It would thus appear that in 1875> 

 as in 1877, the return flights from the Southern States, Iowa, Kansas, 

 and Minnesota, in many cases pass over Dakota into Montana, and 

 probably British America. 

 11 G 



