NORTHERN LIMIT OF SPREAD. 139 



Barry ; the rest of the line through the State is that which was desig- 

 nated by Mr. Riley, iu his seventh report, as the eastern limit of their 

 incursion in 1874, which passes through the following counties : Harri- 

 son, Daviess, Caldwell, Kay, Lafayette, Pettis, Benton, and Hickory. 



Arkansas. — In Arkansas, only the extreme northwest portion appears 

 to have been visited since 18G7, at which time, according to the Monthly 

 Eeport. of the Agricultural Department, they penetrated to Montgom- 

 ery County. Since then, Mr. Riley's reports up to 1876, and our own 

 correspondence for 1877, show that their incursions into this State have 

 extended only over Carroll, Benton, and Washington Counties. 



Indian Territory. — The data in reference to movements in Indian Terri- 

 tory are very meager : that they have reached the eastern boundary as 

 far south as Washington County, Arkansas, since 1867 is certain j that 

 they have also extended east of Fort Gibson is also known positively. 

 The next point south of this reached since 1867, of which we have any 

 certain knowledge, is Grayson County, Texas. But in 1867, when their 

 migrations extended eastward to Montgomery County, Arkansas, they 

 also reached Red River County, Texas ; hence, in all probability, includ- 

 ing all of Indian Territory. 



Texas. — Through Texas the line may be designated by the following 

 counties: Red River (1867, Walsh, and Monthly Rep. Agl. Dept)., Hunt, 

 (Walsh) 5 Anderson, Grimes, Harris, Austin, Colorado, Lavaca, Vic- 

 toria, Goliad, and Live Oak. 



We have been unable to trace them into any of the coast counties in 

 this State, or to the Mexican line on the Lower Rio Grande j yet it is 

 quite possible that swarms have been driven to the gulf shore southwest 

 of Galveston ; but the southeast limit of their range appears to be quite 

 constant in the second tier of counties, seldom reaching nearer than 

 thirty miles of the coast, as we are informed by the United States signal- 

 service officers located in that part of the State. 



By noting on a map the localities given it will be seen that the east- 

 ern limit of their range is marked by the following line : From the south- 

 ern end of Lake Winnepeg, by wa^ of the Lake of the Woods, to Pierce 

 County, Wisconsin j thence almost directly south to Poweshiek County, 

 Iowa ; thence south west to. Worth County, Missouri ; thence, south through 

 Montgomery County, Arkansas, to Houston, Texas, curving westward 

 from this point to Live Oak County. The various bends or flexions in 

 this line are in all probability due to the forests with which the line 

 from the middle of Iowa southward appears to correspond. That this 

 is the case in Southern Iowa and Missouri is certain ; but in Minnesota 

 this rule does not appear to hold good, at least to the same degree as 

 farther south. In Manitoba the eastern and also the northern limit cor- 

 responds very closely with the timber line. 



