I BELIEVE that hitherto nothing has been recorded of the 09co- 

 nomy of these insects; it is therefore with great pleasure that I 

 can give a short account of the species figured : for this infor- 

 mation as well as for specimens of the fly I am indebted to my 

 friend the Honourable C. A. Harris, who informed me that in 

 examining the receptacles of the Pi/rethrum inodorum he dis- 

 covered small maggots and pupae in the centre of a considera- 

 ble number of them, and that eventually one little fly was pro- 

 duced from them. I afterwards had the pleasure of investiga- 

 ting the subject with him, and a great portion of the flowers 

 we gathered in a field near Heron Court contained larvae or 

 pupae, seldom more than one in each ; they produced flies from 

 the besinning; to the end of October, 



Another minute species, which I think is the P. nigra of 

 Meigen (v. 6. p. 191. n. 7.)? was sent to me by a lady, who 

 found the pupae on the underside of the leaves of the Colum- 

 bine (pi. 392.) the 7th of November, and they hatched the fol- 

 lowing May. 



The Plant represented is Pi/rethrum inodorum (Corn Fe- 

 verfew). 



