480 THE CARROT CROP. 



vastafcion as the Haltica nemorum, or " common turnip- 

 fly." No sooner, however, does the young plant appear 

 above the ground, than it is liable to be eaten off by the 

 slugs and snails (see p. 385) so plentiful at that time of 

 the year. As soon as the tap-root is formed, the mag- 

 gots of the crane-fly (Tlpula oleracea, see p. 386) 

 commence their work by eating through the root just 

 below the crown, and effectually arresting its further 

 growth. These, in some seasons are very destructive, 

 entire drills disappearing from their attacks. The 

 young plants, too, suffer considerable injury from the 

 "carrot plant-louse" Aphis dauci which, by generat- 

 ing in the crown of the root, effectually destroys the plant. 

 Later in their growth, the grubs of the " carrot-fly "- 



1 and 2. Larva of Psila rosce (natural size and magnified). 3 and 4. Do. appearing from the 

 galleries excavated in the carrot. 5 and 6. Form of pupae (natural size and magnified). 

 7 and 8. The "carrot-fly" (natural size and magnified). 



Psila rosce make their way to the root, which they 

 penetrate, and then form long galleries through its tissues, 

 by which the circulation of its juices is interfered with, 

 the functions of the roots arrested, and a general injury 

 done to the plant. This is soon shown by its altered 

 appearance; and if the root is taken up, the injury sus- 

 tained shows itself by the ochreous or " rusty " appearance 

 of the part affected, from which the name of "rust" has 



