171 



The grub goes down into the soil in autumn and turns 

 into a chrysalis, forming a cocoon of earth as a bed. It 

 is doubtless advantageous to break up the soil so as to 

 expose them as much as possible to the influence of 

 frost and wet, and to bring them in reach of birds. 

 Many mixtures have been tried in the hope of destroy- 

 ing the grubs, but not with the success that might be 

 desired. A dressing of gas-lime has been found 

 beneficial. Hand-picking has been found useful but 

 expensive ; this, however, is more practicable in the 

 ase of turnips than of potatoes. Constant stirring of 

 the land has a good eifect, but, unfortunately, the 

 damage is done to the potato crop when the tubers are 

 forming, and are consequently moulded up. Starlings 

 and plovers consume a great many, and rooks eat them 

 to gome extent. 



The grub of the Yellow Uiiderwing,^VbciMa (Tryphcena) 

 pronuba, attacks the tubers in much the same manner as 

 do the surface caterpillars, and frequently cause much 

 injury. The caterpillar, the grub of the Great Yellow 

 Underwing moth, is an inch and three quarters in 

 length, and as thick as a stout quill. It is very variable 

 in colour, generally of a sickly green or dull brown, 

 with a dull brown band down the back, a pale line 

 along the middle, and a short line of dark spots or 

 streaks along each side. Underneath it is a pale green. 

 They are fat, and dull in appearance. When exposed 

 they curl up into a ring. They are night feeders, and the 

 means of exterminating them are similar to those recom- 

 mended in the case of the surface-feeding caterpillars. 



