60 [August, 1841. 



Written Communications. Miss M. A. Morris, of Ger- 

 mantown, Pennsylvania, through Dr. B. H.Coates, submitted 

 the following "Observations on the development of the Hes- 

 sian Fly," dated August 6, IS41. 



"Having completed a series of observations on an insect that 

 has for years destroyed the wheat in the neighbourhood of Phila- 

 delphia, I now beg leave to lay them before the Academy of 

 Natural Sciences, with specimens of the insect in all its forms, 

 from the egg to the perfect fly. To those familiar with Mr. Say's 

 description, accompanied by Mr. Le Sueur's accurate drawings, 

 given in the first volume of the Journal of the Academy, no doubt 

 can arise as to the identity of the male insect now presented with 

 the Cecidomyia destructor of Mr. Say; but the female differs 

 materially in colour, her body being entirely black or blackish- 

 brown ; and the wings are destitute of the hairy fringe so con- 

 spicuous in the male. 



In the months of March, April and May, I have frequently 

 found the larva? feeding in the centre of the straw, from the root 

 up to above the last joint. They were then of a pale greenish 

 white colour, translucent, with an internal visceral green line ; 

 mandibles of a dark brown colour. At this early period the larva? 

 have frequently been so small that a magnifying glass has been 

 necessary to detect them, 



In the present year, 1841, my observations were unavoidably 

 delayed until the first of June ; when I found that the larva? near 

 the root had left the inside of the straw, and become pupa? on the 

 outside, under the sheath. On the 20th of June, most of the 

 puparia were empty; and on agitating the wheat, swarms of flies 

 rose from off the grain, where they had been resting. I was for- 

 tunate in obtaining one of these while in the act of depositing her 

 egg on the grain. Thus interrupted, she placed six on my finger. 

 Three of these I have glued to the paper near her. When depo- 

 sited they were of a pale straw colour, and inconspicuous to the 

 naked eye, unless collected in numbers. On the same day, I found 



