THE STATE ENTOMOLOGIST. 103 



"Having crossed the Mississippi at Rock Island the insects soon 

 traversed the State of Illinois and reached the shores of Lake Michi- 

 gan, where it might have met a watery grave, but, unfortunately its 

 course was only deflected southward, and there were other cohosts of 

 the invaders, traversing lower parallels, so that by convergence, the 

 force was multiplied and great fears were anticipated by the potato- 

 growers of Northern Indiana and Ohio, and it was supposed that 

 Northern Ohio would be invaded before the Southern portion of this 

 State. 



" At the last annual meeting of the Indiana Horticultural Society, 

 in January 1868, the existence of this insect was reported in several 

 counties in the north-western part of that State during 1867, leading 

 us to apprehend that the day of their approach to us was not so dis- 

 tant as we had fondly hoped. Correspondents now inform us that 

 this beetle has reached Lafayette, Indianapolis, Danville, and other 

 points of central Indiana, so that its progress eastward continues with 

 increasing speed. 



" We have now to record the actual presence of the Ten-lined 

 Spearman, (Doryphora 10-Hneata,) in the south-western corner of 

 Ohio, a very few specimens of this pest having been taken within the 

 past week in Hamilton county." 



Thus it appears that its average annual progress towards the east 

 has been upwards of seventy miles. At the same rate of progression it 

 will touch the Atlantic ocean in about ten years from now, or A. D. 

 1878. 



" But," it will be asked, " how could any entomologists make the 

 mistake of supposing that the Colorado Potato-beetle had always ex- 

 isted in the Northwestern States ?" The answer is, that, as was proved 

 three years ago in the article already referred to they inadvertently 

 confounded together two entirely distinct, but very closely allied spe- 

 cies, the bogus Colorado Potato-beetle {Doryphora juncta, Germar), 

 and the true Colorado Potato-beetle (Doryphora 10-lineata, Say). 

 The former of these has existed in the South-west from time imme- 

 morial, and has long since been known to feed in the larva state upon 

 the horse-nettle (Solatium carolinense, Linn,) a wild plant which is 

 exceedingly adundant in our own State. In 1863 Mr. Glover stated 

 that he "had found an insect similar to the Ten-striped Spearman [or 

 true Colorado Potato-beetle] on the common horse-neetle in Georgia." 

 ( Ayr. Department Rep., p. 579). In 1867 he assured me that this 

 insect, found by him on the horse-nettle in Georgia four years before, 

 was the bogus Colorado Potato-beetle (D. juncta,) and that u a Mr. 

 Walter had also found it feeding upon the Egg-plant in Montgomery, 

 Alabama." I discovered this same species in Kentucky in 1864, feed- 

 ing in conjunction with its larvae upon a plant, which could have 

 been nothing else but the horse-nettle ; and last fall I met with it in 

 great numbers, in St. Louis and Jefferson counties in this State, feed- 

 ing upon the same plant, in company with its larvae; and in one in- 



