FROM RUSTICUS. 339 



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

 operations Mr. Haliday has so well described. 9 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, driving 

 away the rascally parasite that is for ever hovering about them 

 to destroy them. Believe me ever yours, 



Godalming, I5tk 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-^y, the smaller animal being only the turnip-yfea. 

 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 antennas 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. 



