DESTRUCTIVE INSECTS. 297 



nal leaves which, if they destroy, occasions the loss of 

 the plant. They attack the turnip plant as soon as 

 it appears above ground, and it is astonishing- how 

 soon a field of ten or twelve acres is eaten off. To 

 this disappointment and loss the farmer must submit, 

 and sometimes thrice in the same season, there being-, 

 as yet, no effectual preventive discovered to defend 

 the crop. The most successful management for pre- 

 serving a crop of field turnips is by sowing drills of 

 the kind intended to stand, rather thinly, alternating 

 with drills of another sort, sowed thickly ; the latter 

 will be preferred by the flies, and devoured while the 

 first grow out of their way: the supernumerary drills, 

 if any of the plants escape, are afterwards hoed up. 

 We know very little of the economy of this insect ; 

 like other beetles it passes the three first stages of its 

 existence in the ground, and comes forth sooner or 

 later in the summer according to the heat thereof, or 

 as the chrysalides are exposed on the surface by the 

 plough ; many farmers being of opinion that the 

 aration necessary for the turnip plant, serves to 

 awaken the sleeping insect, 



We had been acquainted with this beetle and had 

 suffered much from its ravages many years, without, 

 ever being able to witness its flight ; but one day 

 (20th July last) passing along the Fulham road, and 

 opposite a piece of turnip saved for seed in the nur- 

 sery of Messrs. Harrison and Bristow, we found several 

 of the insects on our dress, and saw thousands sport- 

 ing in the sunbeams over the crop. This circum- 



