( 11 ) 



the contents of a "flax-seed," I found the larva or 

 maggot within considerably altered. It did not as yet, 

 as far as I saw, show any development of limbs, but it 

 was now changed to a reddish yellow colour, of a 

 brighter red along the back. As these changes of tint 

 are stated by Dr. Wagner to follow almost immediately 

 on the rudiments of the coming wings being observable, 

 it is probable that examination with a better light, or 

 with a stronger microscope-power, would have shown 

 their appearance. 



No. 6. CECIDOMYIA DESTEUCTOK, Say. Hessian Fly, natural size 

 and magnified.* 



The Imago or perfect Fly. 



On the 8th of September the first fly developed from 

 my "flax-seeds " or puparia. This to the naked eye 

 was a stout-made little brown gnat, with darker head 

 and body, legs of rather lighter brown, brown horns, 

 and a pair of smoky-grey wings with longitudinal veins. 

 It was exactly one-eighth of an inch in length. 



In order to note the successive changes in colour 

 occurring up to maturit} r and immediately after death, 

 I observed the specimen at intervals for about three 

 days, and endeavour to give the result as plainly as I 

 can. The fly was first noticed about four in the after- 

 noon amongst my specimens of infested straw, and I 



* The position of the imago is after the fig. /. by Mr. Burgess in 

 plate iv. of paper on Hessian Fly in Third Keport of U. S. A. Ent. 

 Comm. already quoted ; the details, &c., from my own British specimen. 



