430 INSECTS INJURIOUS TO VEGETATION. 



middle of the stem, and, having reached a proper height, escapes 

 from the hollow of the straw to the outside, where it takes the 

 pupa or flax-seed state. The fact that the Hessian' fly does or- 

 dinarily lay her eggs on the young leaves of wheat, barley, and 

 rye, both in the spring and in the autumn, is too well authenti- 

 cated to admit of any doubt. If, therefore, the observations of 

 -Miss Morris are found to be equally correct, they will serve to 

 show, still more than the foregoing history, how variable and ex- 

 traordinary is the economy of this insect, and how great are the 

 resources wherewith it is provided for the continuation of its kind. 

 Various means have been recommended for preventing or less- 

 ening the ravages of the Hessian fly ; but they have hitherto 

 failed, either because they have not been adapted to the end in 

 view, or because they have not been universally adopted ; and it 

 appears doubtful, whether any of them will ever entirely exter- 

 minate the insect. It is stated in the before mentioned Report 

 of " the Philosophical Society," that Miss Morris advises ob- 

 taining " fresh seed from localities in which the fly has not made 

 its appearance," and that " by this means the crop of the following 

 year will be uninjured ; but in order to avoid the introduction of 

 straggling insects of the kind from adjacent fields, it is requisite 

 that a whole neighbouriiood should persevere in this precaution 

 for two or more years in succession." " This result," Miss Mor- 

 ris says, " was obtained, in part, in the course of trials made hy 

 Mr. Kirk, of Buck's County, Pennsylvania, with some seed- 

 wheat from the Mediterranean, in and since the year 1837. His 

 first crop was free from the fly ; but it was gradually introduced 

 from adjacent fields, and, in the present year (1840), the mis- 

 chief has been considerable." In other hands this course has 

 proved of no use whatever. Not to mention other instances, the 

 following appears to be conclusive on this point. About forty 

 years ago, Mr. Garret Bergen, of Brooklyn, New York, pro- 

 cured two bushels of wheat from the Genesee country, then an 

 uninfected district, which he sowed in a field adjoining a piece 

 seeded with grain of his own gathering. Both pieces were se- 

 verely damaged by the Hessian fly, which could not have hap- 

 pened, in the same season, if the eggs, of the insect are laid only 

 on the grain. A few years ago he soaked his seed-wheat in 



