362 THE RAPE CROP. 



mon-fly (Hemiteles melanarius), which breeds in numbers 

 from the pupse. 



1. Butterfly (P. napi). 2. Eggs of do. deposited on leaf. 3. Caterpillar of do. 

 4. Chrysalis of do. 5. and 6. Ichneumon-fly (magnified and natural size). 



The seeding plants are sometimes sadly injured by the 

 " turnip-seed weevil," whose presence is always indicative 

 of a diminished yield. The remedies for the various 

 insect attacks recommended at page 323 are equally 

 applicable to this crop. 



The chemistry of the rape plant has received consider- 

 able attention of late years, owing to the increasing use 

 made of it and its produce, both as a fodder crop and for 

 feeding and manuring purposes. 



We find that the plant in a green or natural state 

 contains about 87 per cent, of water, 11-5 per cent, of 

 proximate organic compounds, and 1 *5 per cent, of ash or 

 inorganic matter, of which latter the composition is thus 

 given: 



Potash, 10-32 



Soda, 3-88 



Lime, 25'45 



Magnesia, 3'25 



Phosphoric acid, 6 '04 



Sulphuric acid, 9'65 



Silica, 1-07 



Chloride of Sodium, 4Q-34 



100-00 



The organic constituents of the plant, upon which its 



