THE TURNIP FLY (Athalia spinarum). 



Some of your readers may not possibly be subscribers to Mr. Curtis's invalu- 

 able British Entomology ; in which case they will not have seen the useful infor- 

 mation his last number contains relative to the Turnip Fly, that pest of farmers. 

 Respecting this insect there is so little known, even among those who are in other 

 respects well-informed, that I strongly recommend an attentive perusal of Mr. 

 Curtis's interesting description. It is not the fly itself that is the author of the 

 damage, at least not in his winged state ; he is, " ut dicam" comparatively inno- 

 cent : but it is his former self — if I may be excused the Hibernicism — to which he 

 is now " unlike, Oh, how unlike !" that causes all the mischief. Having emerged 

 from his " durance vile" he displays a fine yellow body ; but when he was a gro- 

 velling worm of the earth he was clad in sable robes — in mourning, if you will 

 forgive the flight, for the destruction and havoc he was spreading all around him. 

 Then he was confined to the turnip fields ; and if the farmers had only possessed 

 the information which Mr. Curtis has now given, they might have learned a sim- 

 ple and most easy method of getting rid of their countless enemies. If a hurdle 

 is drawn lightly over the field it will brush them off the leaves, and once on the 

 ground they are in their graves ; they cannot make their way over the soil, or 

 ever again ascend the stalk. But now that they are invested with wings they roam 

 wherever their fancy leads them, having first probably deposited their eggs on the 

 turnips, which is the only food on which their larvae can live, as they will not even 

 touch the swedes. Whether the perfect insect affects any particular plant does not 

 appear to be satisfactorily ascertained ; possibly not. Having been so long con- 

 fined, in the larvae state, to one kind of food (from its incapacity to search for 

 any other), it now probably seeks for a greater variety of delicacies than formerly 

 fell to his lot to enjoy. The winged insect appears as early as March, and is visi- 

 ble to the middle of October ; the larvae continue to the same time from about 

 the middle of August. Ducks are particularly fond of the caterpillar, which is 

 most plentiful the beginning of September, and if turned into the fields will eat 

 them with avidity. The larvae abound much more in some localities than others, 

 but are said to have been more abundant this summer than they have been for the 

 last thirty years. In very many fields the leaves of the turnips have withered and 

 turned yellow ; in some instances causing the entire destruction of the root, in 

 others producing an unhealthy appearance. This occurred previous to the plants 

 having attained their full growth, and they did not afterwards make much advance 

 in size ; the blight was upon them, and they looked as if they had been scorched 

 by the hot wind of the desert. Some farmers attributed this destruction to the 

 black caterpillar of which I have been speaking, though I think they are mistaken, 

 as they only eat the fresh leaves, and would find no sustenance in the withered 

 ones ; but the secret, in my opinion, is, that the season which is favourable to the 



