RETURN SWARMS FEEBLE AND DISEASED. 239 



reason to believe that some of tbe insects reached as far as the North 

 Saskatchewan, the movement was by no means so constant nor so gen- 

 eral as in 1875.^"^ 



The locusts which reach beyond the 50th parallel by the middle of 

 June must needs have developed many degrees south, and even were 

 there not actual observations to prove it, such facts strongly indicate 

 the destination of the swarms from the more southern country to be the 

 Northwest. 



The insects which leave the Temporary region are always greatly in- 

 fested by parasites, and are constantly dropping and perishing on their 

 northward course, a fact established by our own personal observations as 

 well as by general experience. Many of them also perish, just as do 

 the young, from disease and the effects of storms. We may very 

 justly conclude, therefore, that a large proportion of the insects which 

 depart from the Temporary region perish on their way toward the native 

 breeding-grounds of the species, and that those which do not so perish 

 reach the high plains regions of the Northwest, whence their parents 

 had come the previous year. *' They are carried back with favoring 

 winds, in thinned ai^d weakened ranks, and those that did not start 

 with the germs of disease, and which escape from other vicissitudes, 

 doubtless succeed in reaching those conditions which favor the contin- 

 ued perpetuation of the species. They do comparatively little harm on 

 the way, and are not, by any manner of means, to be likened to the 

 more disastrous swarms from the opposite direction in the fall." 



The return movement is mostly over the thinly-settled plains regions, 

 and the diseased and debilitated insects may drop and die by myriads 

 in such country without being observed, and we may rest assured that 

 this is one way in which they vanish ; that this is, in fact, the destina- 

 tion of a very large proportion of the returning insects. 



DO THE RETURN SWARMS BREED? 



It is quite important for us to know whether the insects that hatch in 

 the Temporary region continue to breed when they get to the Permanent 

 region ; because, if the permanent breeding-grounds are recruited from 

 the insects which hatch and develop to the southeast, there is all the 

 greater incentive for our farmers to destroy the young insects. The 

 more effectually these are destroyed, the less frequent in this event will 

 be the invasions from the northwest. From the facts at hand there can 

 be no doubt that a portion of the returning locusts do thus breed, and 

 it is our opinion that the propagation of the species is the prime object 

 of the northward flights. It is doubtful, however, whether the issue 



37 The Detroit Record published last fall a statement made to Mr. W. J. Wheeler of that town, to the effect 

 that the " Lake of the Woods " -was " covered with dead frrasshoppers. and all along the southeast shore 

 the dead 'hoppers were over two feet thick." There is nothing improbable in this report, which would 

 indicate that the eastward wing of the northward flights largely perished in that way ; but we have 

 been unable to get corroboration of the fact, and Mr. L R. Bentley, of Saint Frances, who was on the 

 Wood and Rainy Rivers from June, saw nothing of the sort. 



