REPORT OF THE ENTOMOLOGIST. 305 



ucd from now on until into the middle of September, when localities 

 much more widely removed from the breeding center will be reached. 



Up to the time of my leaving the locust area indicated no eggs had 

 been deposited by the Eocky Mountain species, that I heard of, but 

 specimens were seen in coitu at all points where the species were ob- 

 served after August 1. From this fact as a basis it will be safe to pre- 

 dk-t a general deposition of eggs over the entire area visited and still 

 to be visited by the advancing flights. By referring to the records for 

 past years in the United States Signal OfBce at Bismarck, Dak., it was 

 ascertained that the prevailing wind in that region changes from the 

 east and southeast to the northwest about the middle of August ; and 

 as a consequence from tliis time on we may expect more northwest winds 

 tlian we have thus far had since the locusts began their southward 

 movements, and as a natural result a continuation of this movement is 

 to be anticipated. Kow, it depends altogether upon the weather and 

 kinds of winds henceforth this season whether or not any of these arc so 

 directed as to mass tlie locusts at some particular locality, and thereby 

 result in damage to the corn croj). 



The probabilities now are that M. spretus will hatch in moderate num- 

 bers throughout the region this year overrun, and, in addition, through- 

 out the greater i^art of Dakota, as well as parts of Northern Nebraska 

 and Northwest Iowa. Of course, when they have been spread over so 

 extended an area, there can but little harm emanate from the com- 

 paratively small swarm which produced them. The only chance now 

 of injury from locust swarms next year is in the possible accumulation 

 of numbers during the present fall, while they are still moving, and 

 before the majority of their eggs have been deposited, or in a like ac- 

 cumulation after the young of next year's hatching have become fledged 

 and begun their flights. S uch a state of affairs 'can only come to pass 

 by the aid of extremely favorable circumstances, and when we take into 

 consideration the numerous adverse agencies which in ordinary years 

 rather deter than promote the highest possible development of the spe- 

 cies, we need not fear any such calamity. The chances for such an in- 

 crease are diminished at least one-fourth by the fact of the summer thus 

 far having been a rather exceptionally humid one, and the chances are 

 that the fall wiU continue similarly wet, which, if followed by an open 

 winter, will have the same effect ujDon the hatching of the eggs as did 

 that of lS7G-'77. 



One fact particularly noticed this year is the comparatively few para- 

 sites of every species that are known to destroy this and other locusts. 

 While in Montana and Dakota I became interested in no small degree 

 in noticing the almost total absence of certain parasites which had been 

 seen in the same localities several years ago in rather large numbeie. 

 I therefore took particular pains to watch for these beneficial insects, 

 and, as a result of these observations, I am sorry to say there is but 

 little need of looking to this quarter for aid in checking the already 

 greatly advancing increase of locusts in Montana and Northwest Da- 

 kota tiie coming summer. This scarcity of these natural aids of man in 

 this particular direction can be attributed to no other cause than the 

 \'ery dry seasons of 1882, 1883, and 1884 in this particular region, in 

 connection with the absence of the Eocky Mountain Locust from the 

 greater portion of the country since 1878. All these parasites appear 

 to thrive best, and many of them, on account of their delicate structure, 

 are greatly dependent for their development upon a considerable amount 

 of humidity. The present wet summer may, however, have a tendency 

 to increase their numbers again. 

 20 AG— '85 



