224 Season of 1816. 



Philadelphia, September 28, 1817. 



Sir, 

 It is a circumstance not a little singular, that the Hes- 

 sian fly is unknown to the Europeans ; such, however, 

 from all I can learn, appears to be the fact ; but the name 

 is at the same time perfectly familiar to them, particular- 

 ly to their entomologists, but as it has no meaning of it- 

 self, and no analogies upon which it depends, it conveys 

 no information to them : here then is one of the uses of 

 a scientific arrangement and an universal nomenclature. 

 The classical name refers directly to a natural assemblage 

 whose habit is the same, or nearly so, hence every ento- 

 mologist who learns the name of an insect, becomes at 

 the same time acquainted with the general form of the 

 body, manners, mode of life, &c. The European ana- 

 logue of this famous insect, (tipula tritici, Kirby,) depre- 

 dates upon the blossom of the wheat, and its attacks are 

 always confined to the contents of the calyx ;* our species 

 I believe is not known to infest that part of the plant. 

 The plate you received was drawn and engraved by Mr. 

 C. A. Le Sueur, a justly celebrated zoologist and drafts- 

 man, it is printed in black ; this I mention particularly, 

 as two or three of the impressions were coloured capri- 

 ciously, and were taken by some of the members of our 

 academy ; if, perchance, the one in your possession is 

 coloured, I will furnish you with a proper impression. 



* This seems to be the spotted moth fly of the southern states ; 

 which lays its egg on the blossom of the wheat. It is hatched in 

 the ^rain ; and, when perfect, eats its way through the envelope 

 of the wheat, like the pea bug. It differs entirely from the Hes- 

 sian fiv : both in its mode of propagation, and its habits. R. P. 



