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ried about are, almost without exception, either from the west, 

 northwest, or southwest, or toward Buffalo instead of from it. 



No one knows better than I do that Mr. Howard does not write 

 such papers as his for the sake of theorizing, or for the purpose 

 of getting into print, but with the sincere hope of furthering the 

 interests of a science to which he is giving the best years of his 

 life ; and for this reason these facts are given as additional infor 

 mation on the subject, and probably not in his possession when 

 he wrote his paper ; and far more in the spirit of a colleague 

 than that of an opponent. His paper is an excellent one, and 

 would have been of value even had he not shown the growing 

 necessity of keeping records of exact locations, and giving more 

 exact information on that point than to say that a species occurs 

 in such and such States, or from such a State to such a State, 

 as we have been in the habit of doing heretofore. 



There are so many factors that influence insects that the prob 

 lem of geographical distribution, as well as the phenomena of 

 their differentiation, becomes not only interesting but sometimes 

 exasperatingly perplexing, especially in the case of introduced 

 species. It would, indeed, be an achievement in economic ento 

 mology if we could say of a species, it will reach only a certain 

 locality, or it will not prove destructive beyond a certain well- 

 defined boundary. For my own part, some of our native species 

 that are moving from the south northward are puzzling me quite 

 as much as those that are reaching Ohio from the east, not that 

 it is at all strange that southern species should, some of them, 

 work northward, even from Central America, but I would like to 

 know where the things are likely to stop in their migration, and 

 if, when they appear to have reached their limit of range, they 

 have stopped for good, or if, after I have stated beyond revision that 

 they will not continue northward, they do not suddenly break out 

 in destructive numbers far beyond the area that I have assigned to 

 them. In short, I would be glad to learn, beyond a doubt, 

 whether or not there is some natural barrier to their progress be 

 yond certain lines that can be so clearly indicated that the public 

 may see and understand. 



Murgantia histrionica, as is well known, has been steadily 

 working its way northward from Texas since 1865. In the Sixth 

 Report of the State Entomologist of Illinois Dr. Cyrus Thomas 

 records the appearance of the species in Jackson county of that 

 State, but in a recent letter from Prof. G. H.French, of Carbon- 

 dale, I have the information that the announcement was probably 

 a mistake. Prof. French says that he has a single specimen from 

 somewhere in southern Illinois, he does not know just where, but 

 that the insect is not destructive or even common, so far as he is 

 aware. I think it was in 1890 that it was reported from Tobins- 



