J 3^ ENTOMOLOGICAL NEWS. [May 



DEPARTMENT OF ECONOMIC ENTOMOLOGY 



Edited by Prof, JOHN B. SMITH, Sc. D., New Brunswick, N. J, 



Papers for this department are solicited. They should be; sent to the editor. 

 Prof. John B. Smith, Sc. D., New Brunswick, N. J. 



A CONTRIBUTION TO A KNOWLEDGE OF THE FAUNISTIC 

 LNTOMOLOGY OF OHIO.* 



By F. M. Webstek. 



During the last seven years I have been able to study the insect 

 fauna of Ohio with more or less care, and have been much impressed 

 by the rapidity and trend of diffusion in several species of insects, 

 some of which have appeared within the boundaries of this State 

 since a comparatively recent date. Insects make their way into 

 Ohio from other States, coming from almost all points of the com- 

 pass, except the North, which is protected, to a large extent at 

 least, by Lake Erie. As my duties have obliged me to pay particular 

 attention to such species of insects as possess habits of economic in- 

 terest, I have studied these with greater care, and, in fact, others 

 may have made their way into the State without my having observed 

 them. However, injurious insects have some characteristics which 

 tend to give them a value in faunistic studies, for, though they must 

 become quite destructive befoi-e they are likely to attract the atten- 

 tion of the husbandman, yet often the time *ind place where their 

 depredations are first observed offers no mean basis for working out 

 the problems of introduction and diffusion. In a majority of cases, 

 perhaps, an insect will have made its appearance a number of years- 

 before it will be discovei-ed by entomological collectors, and then it 

 may be several years before it has increased in sufficient numbers to 

 become destructive. But, other things being equal, it is likely to 

 become a pest fii-st somewhere near the point where it first gained a 

 foothold. The data here given, while not as full in all cases as 

 could be wished, yet it is not only the best that can be secured at 

 present, but it is practically all that we have on which to base fu- 

 ture investigations of this character. This information has been se- 

 cured by personal observation and by cori'espondence, the latter 

 being used alter rigid inspection and sufficient evidence of its accu- 

 racy obtained . 



The direction taken by a species on first entering the State is often 

 influenced by rivei's. Perhaps this element has had a greater influ- 

 ence than any other in shaping, directly or indirectly, the course of 

 diffusion in a majority of the species included in this paper. Rail- 

 ways come in for a share of the credit for diffusing some species, w hile 

 commerce also may be credited with shaping the course of other spe- 

 cies. Of course the most potent factor in both shaping and defining 

 * Read before the Ohio State Academy of .Science, December 29, 1898. 



