FROM RUSTICUS. 339 



the aphites from the attacks of that little parasitic fly, whose 

 operations Mr, Haliday has so well described.^ You must 

 have seen a sheep-dog run over the backs of a whole flock of 

 sheep, when closely crowded together, in order to bring back 

 some sinner that has gone astray ; so will the ants in the hot 

 sunshine run about over an establishment of aphites, drivint»- 

 away the rascally parasite that is for ever hovering about them 

 to destroy them. Believe me ever yours. 



Godalming, 15th August, 1835. 



P. S. I forgot to tell you that all our turnips this year are 

 destroyed by the blacks; and I begin to think that these are 

 the real turnip-^?/, the smaller animal being only the turnip-^ea. 

 About the middle of July these real turnip-flies were showered 

 down on us, as it were from the clouds ; they fell thicker 

 than rain drops, and hovered about the turnips in such 

 myriads that the whole fields were coloured with a rainbowy 

 tinge, when the hot sun shone on the filmy gauzy wings of the 

 flies. I will give you an entomological description of one of 

 these flies : — the head and antennae are as black as a coal : 

 the thorax is yellow before and on the top, but coal black on 

 the sides and behind : the body is yellow : the wings are clear 

 and very shining, and tinged with yellow, and the upper ones 

 have a dash of coal black along the upper margin, which 

 reaches three quarters of the way from the thorax to the tip of 

 the wing : the legs are yellow, spotted with black. I could 

 not find that these flies tasted the turnips ; they only came to 

 them on family business. 



About the 9th of August the turnips began to look queer ; 

 the flies had disappeared almost entirely before this, you must 

 recollect. One Saturday I looked well over them, and found 

 they were swarming alive with little black caterpillars. I told 

 two or three men who were hoeing them that the turnips 

 looked bad, and I showed the grubs to them, but they thought 

 nothing of it, and I found I could not persuade them that any 

 thing was the matter. On Sunday I could not get out as far 

 as a turnip-field. On Monday I went out and the turnips 

 were not: they had in two short days been swept from the 

 face of the earth. The land was every where as bare as on the 



a Ent. Mag. Vol. II. p. 98. 



