206 The Hessian Fly. [April, 



The elm is a poor kind of w^ood; and it is rich in potash. 

 Whether cause and etiect, as intimated, are well put together, 

 cannot be regarded as settled. Hickory wood burns well, and is 

 rich in lime: elm, and some other substances, are rich in potash, 

 and burn badly. 



Fungi injure trees, by absorbing the alkalies and phosphates. 

 They draw off" the supply of these important matters, which seem 

 more especially designed for the perfection of fruit and seed. In 

 addition to this, they destroy the tree, by favoring the extension 

 of the decayed spot upon which they first fix themselves. Not a 

 lichen or fungus, which grows upon the trunk or branches, feeds 

 upon air. They all depend upon the juices of the plant; and 

 hence divert from their channel many currents of food, designed 

 for the growth of the plant, and the perfection of its fruit and 

 seed. 



CONTROVERSY RESPECTING THE HESSIAN FLY. 



[We need not apologize to our readers for admitting the discus- 

 sion relative to the Hessian fly. The question is one of great 

 importance to the farmers of Western New-York and elsewhere. 

 W^e hope and expect that, as it is in competent hands, it will be 

 set at rest in the end, by their mutual observations. We expect 

 Dr. Fitch will reply in the May number. — En.] 



Having, through the kindness of a friend, received the second 

 number of your Journal, containing Dr. Fitch's instructive and 

 interesting article on the Hessian fly (Cecidomyia destructor), I 

 beg leave to offer, through the same medium, my thanks for the 

 kind manner in which he differs from me in opinion; and crave 

 his indulgence while I point out a slight error in his statement, 

 which has arisen from misinformation. 



After referring to the theory advocated by rae, in the Trans- 

 actions of the American Philosophical Society, Philadelphia, in 

 1840, and Dr. Coates's communication to the Academy of Natural 

 Sciences, in 1841, and published in the Journal of their proceed- 

 ings, he goes on to state, in page 11, that Miss Morris's theory 

 has been proved to be incorrect, and that " M-e have met with no 

 further attempts to sustain it;" consequently, that it has not been 

 sustained. 



If Dr. Fitch will have the kindness to refer to the August num- 

 ber of the Proceedings of the Academy of Natural Sciences, he 

 will find a full statement of my observations during the summer 



