252 



INJURIOUS IXSECTS 



seen, and there is every reason to believe that he has no 

 existence. Xor does the female ever acqui]-e vrings. It 

 is but a transient sumraer state, not at all essential to 

 the perpetuation of the species, and does, compared with 

 the other type, but trifling damage. 



As already indicated, the antnmnal individuals of gal- 

 licola descend to the roots, and there hibernate. Tliere 

 is every reason to believe also that, throughotit the sum= 



Fig. 15i.— GEM'S PHYLLOXERA, ROOT-IKHABITLNG TYPE. 



a. Roots of Clinton vine, showing relation of Swellings ro Leaf-galls, and power of 

 resisting decomposition ; Larva as it appears when hibernating; c, d, 

 Antenna and Leg of same ; e. -f. o. Forms of more mature Lice ; 

 7i, Granulations of Skin ; i, Tubercle. 



mer, some of the yonng lice hatched in the galls are 

 passing on to the roots; as, considering their size, they 

 are great travellers, and show a strong disposition to 

 dro23, their natural lightness enabling them thus to 

 reach the earth with ease and safety. At all events, we 

 know^ from experiment, that the young gfllicfAa, if con- 

 fined to vines on which they do not normally form galls, 

 will, in the middle of summer, make themselves perfectly 

 at home on the roots. 



