30 DISTRIBUTION AND DISPERSION OF LEPTINOTARSA. 



the State. The recorded dates and occurrences make the spread seem rapid, 

 while in reality they are merely notices of first damage to crops. In the 

 following year the insect was more numerous and covered more new ground 

 to the east. 



1868. Several important and interesting records are found in the annals 

 of this year. In the north Gilman (1870) states : " Last summer (1868), to 

 my sure knowledge, it had reached the south shore of Lake Superior and the 

 northwest corner of Michigan, where it abundantly manifested its presence." 

 In Minnesota it was found in Houston County (Am. Agr. , vol. 27, p. 248, 

 1867), and in southwest Michigan it was reported as numerous by Gage, 

 who kept careful records of its numbers, ravages, habits, and foes. Gage 

 states that it was abundant at Dowagiac, Cass County, and appeared for the 

 first time at Decatur, Van Buren Count}', 12 miles northeast of Dowagiac. 

 We know nothing of its distribution in the southern counties of Indiana, 

 but in the northeastern it continued to move slowly eastward, reaching nearly 

 to the Ohio State line. Dodge records the beetle as injurious in Columbia, 

 Jackson, Green, Lake, Brown, Vernon, Douglas, and Bayfield Counties, 

 Wisconsin, in Appanoose County, Iowa, and in Ford County, Illinois. 



In this year is recorded the first unquestionable introduction in advance of 

 the general horde. The editor of the Ohio Farmer (July, 1868) writes as fol- 

 lows: "We have now to record the actual presence of D. 10-lineata 



in the southwestern corner of Ohio, a very few specimens of this pest having 

 been taken within the past week in Hamilton County." The main body of 

 the beetles was still o ,T er 100 miles away. This introduction seems to have 

 come from the region of Cairo, Illinois, or St. Louis, Missouri, by means of 

 the steamers or barges which are constantly passing up and down the Ohio 

 River. I am sure that the coal barges which go down the river from Pitts- 

 burgh, Pennsylvania, have carried into the States along the Ohio River, and 

 perhaps also into the lower Mississippi Valley, many of these beetles from 

 Pennsylvania and Ohio. In August, 1900, at McKeesport, Penns3'lvania, I 

 counted 52 of these beetles on one barge of a " tow " loaded and on its way 

 to New Orleans, Louisiana, and as there were eleven barges in this " tow," 

 it is a low estimate to say that altogether it was probably carrying 300 or 400 

 beetles south into the lower Mississippi Valley. The vicissitudes of such a 

 journey are great, but it would seem that at least 1 or 2 per cent of these 

 beetles might stand a fair chance of reaching the lcwer part of the river valley 



1869. The river barges are probably also responsible for the occurrence 

 of the beetle so far ahead of the general horde, not only in Hamilton County, 

 Ohio, but also in the region about Louisville, Kentucky, where it was 

 recorded in the following year (F. J. Key, letter to Riley in 1871). The 

 beetle was less abundant in this year than during the previous one, doing 

 but little damage and attracting but little attention. In the following year 



