DISPERSAL, Ol-* I.. DECEMWNEATA. 33 



back along the southern shore of Lake Erie to western New York and Penn- 

 sylvania ; thence in a southwesterly direction to the Ohio River Valley, and 

 having followed closely along the valley to Cairo, Illinois, passes westward 

 across the lower part of Missouri into Kansas (plate S). 



rSj2. Over the whole of the area occupied by this beetle there was a 

 decrease in numbers this year, which, in Wisconsin, amounted to over 

 50 per cent. Dodge also states that in Michigan, Ohio, and Illinois the 

 beetles were not as abundant as in 1871 ; that in Missouri they were 

 numerous in Phelps, Perry, and Franklin Counties, and were spreading 

 south, but had not yet reached the southern counties, and that in Kansas 

 they were found in small and constantly decreasing numbers. Along the 

 Ohio River they extended east to Harrodsburgh, Mercer County, Kentucky 

 (J. B. Clark, letter to Riley, 1872). In Ohio they were found in every 

 county in the State (Klippert, Rep. Sec. Sta. Bd. Agr., 1872), while S. S. 

 Rathborn reported to Riley that the beetle had appeared in Lancaster County, 

 Pennsylvania. This latter introduction, so far ahead of the main body of the 

 beetles, probably took place through the agency of some cargo, and was 

 important in determining the spread of the beetles to the south and east, and 

 in enabling them to reach the seacoast a year or two earlier than had been 

 predicted by Walsh. 



In Canada, dementi records the beetle from North Duro, in Peterboro 

 County, Ontario. The following agricultural societies also report its presence: 

 Addington, Bothwell, Brandt (S.), Durham (W.), Elgin (E.), Essex, Fon- 

 tenac, Grey (S.), Hastings (N. and E.), Lamberton, Middlesex (N., W., 

 and E.), Niagara, Norfolk (N.), Northumberland (W.), Oxford (N. and S.), 

 Perth (S.), Peterboro (E.), Simcoe (S.), Victoria (S. ), Welland, and Welling- 

 ton (N. and S.) (Rep. Comm. Agr. Ont., 1872). It gradually spread eastward 

 through Ontario, reaching Kingston in September (Rogers, 1872). It was 

 abundant in most of the western counties of the Province of Ontario, but did 

 comparatively little damage. 



The boundary, which in Wisconsin and Minnesota changed but little from 

 that of the previous year, crossed Lake Michigan in the region of Manistee- 

 and passed due east across the State and through the northern part of the 

 Province of Ontario to Kingston, whence, turning back, it retreated along 

 the northern shore of Lake Ontario to the Niagara River, crossed over, and 

 then followed the southern shore of the Lake and inland to the region of 

 Syracuse, New York ; thence southeast in a tongue-like projection to El- 

 mira, New York ; then back along the shore of Lake Erie. Here there is 

 another tongue- like projection into western Pennsylvania, and then the line 

 turns back and westward along the Ohio River Valley, with the beginning 

 of tongue-like projections into West Virginia and Kentucky. 



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