388 



Observations on the Turnip Saw -Fly. 



Hoeing an attacked crop the most fatal experiment^ until all 

 the caterpillars have disappeared. 



Drawing a cart-rope over the turnips to shake off the caterpil- 

 lars has proved more or less effective, most so when a brush made 

 of elder-boughs has been fastened to it. 



An axletree with wheels, the former armed with green furze, 

 drawn along the rows, wounds and destroys the larvae^ as will also 

 a hushed hurdle. 



Brushing the larvae off with live twigs and stamping upon them, 

 a man following w^ith a scujffler, has cleared a field of the larvae. 



A judiciously cut will often preserve a portion of a field, 



or an adjoining one. 



Hand-picking, when the larvae are not excessively abundant, 

 may be depended upon as a certain remedy; and when in great 

 numbers they may be brushed into sieves. 



Pigs will destroy the black caterpillars. 



Ducks and poultry will devour them with avidity ; and this 

 seems to be the most easy and effectual method of extirpating the 

 black caterpillars : the birds may either be carried or driven into 

 the field, according to the distance. 



Sheep driven over fields infested with the caterpillar have done 

 essential service. 



EXPLANATION OF THE PLATE. 



Fig. 1. The eggs of the turnip saw-fly deposited in the leaf. 

 Fig. 2. The larvae or caterpillars feeding and at rest. 

 Fig. 2 a. One of the fore legs magnified. 



Fig. 3. The cocoon, open at one end, after the fly has emerged from it. 

 Fig. 4. The larva, as seen in the winter, when a cocoon is opened 

 longitudinally. 



Fig. 5. The pupa ornympha in a cocoon, opened longitudinally in the 

 spring. 



Fig. 6. The male turnip saw-flv, considerably magnified ; the cross 

 lines showing the exact natural dimensions of a living fly. 



Fig. 7. The female fly, the size of nature; some specimens, however, 

 are a little smaller. 



Fig. 8. The head of a caterpillar, showing a front view of the face, 

 which is highly magnified, as well as all the following figures : 

 h The minute eyes. 

 c The short antennae. 

 d The mouth. 



Fig. 9. The various organs of the mouth of the caterpillar separated : 

 e The lahrum or upper-lip. 

 / One of the mandibles or teeth. 



