82 First Report on Economic Zoology. 



emitted tliroiigli this. Buckler quotes a letter from the Hon. T. de 

 Grey as follows : — " I first observed the larva by pulling up, on the 

 14th May, a sickly-looking plant of Uquisetum arvense. It appeared 

 to be feeding on the root and stem below the surface of the ground, 



Fig. 9. — the potato stem-borer {HydrcBcia micacea). 



a, Imago ; 1) ami d, larva ; c, pupa ; e, hole in potato haulm caused by larva. 



(Natural size). 



but when placed in a bottle with a supply of the food plant, it 

 immediately entered a stem, and fed upon the inner substance, 

 hollowing it completely out, and ejecting the frass at the lower end." 

 This describes the way it has been observed working in potato haulm. 

 They work with great rapidity, eight inches being tunnelled in an 



