GEOGRAPHY OF NORTH AMERICA. 225 



meridian. Mr. Riley chose for bis examination the southern 

 half of the district east of the Rocky Mountains that is, 

 south of Denver, or the fortieth parallel ; also the western 

 part of Iowa, and, conjointly with Dr. Packard, British Amer- 

 ica. Dr. Packard took also the entire region west of the 

 Rocky Mountain range ; and Mr. Thomas the district east 

 of it lying north of the fortieth parallel. They hope to ar- 

 rive at a complete understanding of the nature of the breed- 

 ing-places of this dreadful scourge; the natural limits of its 

 distribution east, west, and north; the area of its past inva- 

 sions; the exact nature of its migrations; and what species 

 it is which is injurious upon the Pacific coast. They will 

 also make experiments to determine the comparative value 

 of preventive measures. 



The commission was appointed late in March, and early in 

 April Mr. Riley was on his way to Texas. In May and June 

 he visited Kansas; in July, Colorado; in August and Sep- 

 tember, Ontario and Manitoba. Mr. Thomas made several 

 visits to Nebraska, Minnesota, and Iowa. Dr. Packard chose 

 the westernmost field, and made two journeys. On the first 

 he went to Colorado, Wyoming, and Utah ; then turned north 

 through Eastern Idaho and Central Montana to Fort Benton, 

 and followed the Missouri 1200 miles to the western limit of 

 the Northern Pacific Railroad. On his second trip he trav- 

 elled directly to California, and from Sacramento went by 

 way of Shasta Valley and Portland, Oregon, to Wallula, on 

 the Columbia, and then north through Washington Terri- 

 tory to the British boundary, returning to California by sea. 

 The commission therefore covered in a cursory way the en- 

 tire territory, securing a general view, which future seasons 

 may enable them to fill to better advantage. The district 

 examined by Dr. Packard was the newest, and in some re- 

 spects the most important. On his first journey he collect- 

 ed data tending to prove that the breeding-ground of the 

 locust (Caloptenus sjwetits) includes a vast region between 

 longitude 102 W. and the Rocky Mountains, and even ex- 

 tending beyond them in certain parts of Montana. On his 

 second journey he found he must place the limits of its range 

 much farther, so as to include almost the entire country be- 

 tween the Rocky Mountains and the Sierra Nevada; and 

 the general result of his studies seems to be that the perma- 



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