SCIENCE 



NEW YOEK, FEBRUARY 3, 1893. 



SOME INSECT IMMIGRANTS IN OHIO.' 



BY F. M. WEBSTER, OHIO AGRICULTURAL EXPERIMENT STATION, 

 WOOSTER, OHIO. 



In the following paper the term immigrant is to be understood 

 as given in our lexicons, viz: a species that has come to this 

 State from elsewhere and taken up its permanent abode in our 

 midst. While such species are largely of foreign origin, yet this 

 is not true in all cases, and the term foreign is hereafter intended 

 to apply to territory outside of the State of Ohio. Nor do I in- 

 tend to enumerate all of the foreign species that have gained a 

 residence within the boundaries of the State, but to give some 

 facts relative to the time, place and method of introduction of a 

 number of them. Without wishing to present a paper on Econ- 

 omic Entomology, it will be necessary to use, as illustrations, in- 

 jurious or beneficial species, from the fact that these are more 

 closely watched and their movements best understood ; but among 

 the earlier known species we find that even these are often diffi- 

 cult to follow in their advance across the country. There are, 

 seemingly, two what we may term gateways through which the 

 majority of species that have come to us from the east, have made 

 entrance into the State, and, later, spread out over the north- 

 west. The first, and apparently the most important one of these, 

 being at the extreme northeastern part, adjoining Lake Erie, and 

 which we might term the north gate, and, second, the valley of 

 the Ohio River, from a point where it begins to form the eastern 

 boundary of the State, southward — perhaps to Wheeling, W.Va. 

 Now, there also appear to be two great national avenues or high- 

 ways which insect migrations follow ; progressing more rapidly 

 along either one or the other, but not equally so along both, and 

 often following only one; the more sub-tropical species, whether 

 American or introduced, taking the southern or what I would 

 call the Great Southwestern route, while the sub-arctic, includ- 

 ing, besides American, such species as have come to us from Eng- 

 land or Europe north of latitude 45° north, take what I would term 

 the Great Northwestern route. The division between these two 

 great tlioroughfares will 'be indicated, approximately, by a line 

 drawn from New York City, latitude 40° 43' north, to St. Louis, 

 Missouri, latitude 38° 38' north, thence to Pueblo, Colorado, lati- 

 tude 38° 17' north (about), the line of separation trending north- 

 ward, east of St. Louis, under the influence of the Gulf Stream 

 and the Great Lakes, chiefly the former. Of course it is not to be 

 understood that this line is direct, as it is doubtless more or less 

 irregular, and, from its very nature, to some extent unstable, nor 

 is it to be supposed to form a radical boundary, as some northern 

 forms gradually work their way south of it, and vice versa. Yet 

 it will, I think, be found appi'oximately correct. 



One of the first species to push its way across our country vpas 

 the Angoumoise Grain Moth, Sitotroga cerealella Oliver. From 

 the best information we can obtain, it seems to have been intro- 

 duced into this country from southern France, as early as 1728, 

 occurring at that time in North Carolina. This is a southern 

 species, and it is no way likely that it entered from the north, 

 but found its way into Ohio, where it appeared, probably about 

 1840, from Kentucky. It has not, so far as I am aware, been 

 observed in any considerable numbers north of the line indicated, 

 but has pushed its way to the southern part of Texas. The wheat 

 midge, Diplosis tritici Kirby. which probably came to us from 

 England, via Quebec, Canada, entered the United States through 

 northern Vermont in 1838-29, i^ushing southward and westward, 

 but seemingly making more rapid progress to the west. This 



1 Read before the Ohio Academy of Science, Dec. 29, 1893. 



certainly entered Ohio through the northern gateway, over- run- 

 ning the State, as also Indiana. Though reported, first in 1843, 

 and again in 1847, in central Ohio, it was in 1849 reported in de- 

 structive numbers along the northern part of the State, while the 

 eastern and southern portions seemed exempt. Therefore, I con- 

 clude that it came to the State through the north gate. It is one 

 of the species that has followed both the northwestern and south- 

 western routes, but has probably made more rapid progress and 

 advanced farther along the former. Of the early movement of 

 the Hessian Fly, Gecidomyia destructor Say, in Ohio, I have no ex- 

 act data. It might have come up from the South, or entered by 

 either of the two eastern gateways. Like the wheat midge, 

 however, it appears to have made more rapid progress north of 

 the line than south of it. The Imported Cabbage butterfly, PierU 

 rapw Linn., a native of England, but first appearing in this coun- 

 try in the vicinity of Quebec, Canada, in 1860, pushed its way 

 southward, and in ten years had reached southern New York. 

 From here it gradually moved to the west and south, being first 

 observed in Ohio, about Cleveland, in 1873, a year earlier than 

 elsewhere in the State. From this we infer another entrance 

 through the north gate. Though spreading southward, so that 

 the line given does not at present mark the boundaries of its ha- 

 bitat, yet it flourishes best near or to the north of it, and is not 

 nearly so abundant in the Gulf States, though reintroduced into 

 South Carolina in 1873 and in Florida in 1874. It has mainly fol- 

 lowed the northwestern route, but, like the wheat midge, its south- 

 ern boundary lays far south of the line. The three clover insects, 

 Gecidomyia leguminicolaUmt. , Hylesinus trifolii Muel., Pliytonomus 

 punctatus Fab., without exception, I believe, first came to us 

 from the north-east ; though the last two are now known to occur 

 in extreme southwestern Ohio and south-eastern Indiana. They 

 probably entered the State from the south east by way of the Ohio 

 River, at a later date, there being none continuous of the northern 

 colonies to the southward so far as 1 have been able to observe 

 or learn. The Pliytonomus, two specimens of which were, last 

 spring, found by Mr. Dury near Cincinnati, I feel confident was 

 carried into the Ohio River by some of its smaller tributaries, one 

 of which, Beaver River, rises in north-eastern Ohio, by the ex- 

 ceedingly high waters of last spring, and conveyed down by the 

 current and left along the shores. 



Hylesinus may have been introduced in the same manner, but 

 probably several years earlier, as it has already become abundant 

 enough to prove destructive in Dearborn and Franklin Counties 

 in Indiana. 



The Horn Fly, Hiematohia serrata Rob-Desv., probably came 

 first from the north-east, followed almost immediately by an in- 

 dependent introduction by way of the south-east gateway. Com- 

 ing originally from France, this species, in spreading over our 

 country, does so entirely regardless of the lines we have drawn. 

 Siill, its more rapid jirogress along the southern route, where the 

 facilities for its diffusion are much inferior to those along the 

 northern route, where it has made even less rapid progress, 

 shows that it is swayed by the same influences that have directed 

 the course of other species. So far, we have been dealing largely 

 with species of trans-Atlantic origin. Now we will take an 

 American species— the Locust Borer, Cyllene robinm Foist. This 

 species had for upwards of a century been known in New York, 

 as an enemy of the Black Locust, Rohinia pseudacacia L. Some 

 time about the year 1850 it began its invasion westward across 

 northern Ohio, Indiana and Illinois, reaching tlie Mississippi 

 River about 1865, carrying death and destruction to the Black 

 Locust along its path, but not at once extending its ravages, to a 

 serious degree, in the southern portion of these States. Again, 

 reversing the order of migration that we have been following, we 

 will take another American species, Doryphora \0-lirieata Say. 



