INJURIOUS INSECTS. 241 



time ; and from that, as a central point, it seems to have extended 

 in nearly all directions. In this vicinity, one hundred and twenty- 

 five or fifty miles south of the locality above indicated, it was cer- 

 tainly observed in 1830 ; and in 1832 the wheat crops were so com- 

 pletely destroyed by it, as to lead to a general abandonment of the 

 cultivation of this grain. Having spread east over Vermont and 

 New-Hampshire, it in 1834 appeared in the State of Maine, and 

 continued lo advance in that direction, it is said, at the rate of twenty 

 or thirty miles a year. Westward its progress would seem to have 

 been less rapid, and along the Mohawk river by no means so gene- 

 rally destructive. It is not till within a year or two past, that it has 

 appeared in the Black river country east of Lake Ontario, as I am 

 informed by an intelligent gentleman resident there ; nor until the 

 present season that it has been so injurious as to induce in some 

 instances a premature mowing of the crop, and preserving it for hay. 

 Rumor states that farther west, in the wheat-noted Genesee country, 

 it has been detected for the first time the present year. 



The history of its career, appears to be quite uniform in most of 

 the districts hitherto visited by it. About two or three years after 

 its first arrival at a particular locality, it becomes most excessively 

 multiplied, and the devastations which it now commits are almost 

 incredible. Though I believe that through unduly excited fears, or 

 a hope of thereby destroying hosts of this marauder, a mowing of 

 the crop whilst yet green, and a curing of it for hay, has often been 

 resorted to, when, had it been harvested as usual, a less sacrifice 

 would have been made ; yet many cases have occurred, in which 

 diligent search by different persons has failed to discover a single 

 kernel of grain in any of the heads of an entire field ! 



This havoc, so extreme and general, though not universal (for 

 some fields even now escape with comparatively little injury), lasts 

 but one or two years. The numbers of the pest, and its consequent 

 ravages, soon become sensibly diminished ; and after the lapse of a 

 few seasons, the cultivation of the wheat crop is again found to be 

 comparatively safe, and its yield only in isolated instances mate- 

 rially lessened by the continued presence of the fly, which has now 

 become probably a permanent inhabitant. 



It is commonly supposed that this rapid diminution in the num- 

 bers of the wheat-fly has been produced by the general abandon- 

 ment of the cultivation of wheat in this section of the country ; that 



