97 



through the tissues of the potato. (Fig. 108.) Whenever 

 it is attacked in this manner the potato acquires 

 a disagreeable odour and will not be eaten by stock. 



Fig. 108. Sweet potato attacked by Scarabee. 



Reduced. (Original.) 



The eggs are laid in the potato, the grubs and pupae 

 (Fig. 109) occur there, and the adult beetles mate 

 when they emerge and the female deposits eggs in the 



Fig. 109. Scarabee or Jacobs. 

 Pupa. Enlarged. (Imperial Dept. Agrie.) 



same potato. The first attack on a potato may result in 

 a slight infestation at one end the end nearest the 

 surface of the ground. The generation of adult beetles 

 from this first attack spreads to a larger portion, and 

 it may happen that the attack of a third generation 

 can be traced in the potato. The life-history of the 

 scarabee occupies a period of about thirty days. The 

 grubs sometimes occur in the older portions of the stem 

 just above the roots. 



