158 [_ PVAN Ta LICE? 
swollen and broken, and finally the outer portion decomposes and 
rots, and the roots ultimately die. With the multiplication of the 
root lice and their extension to all parts of the root system, the 
vine stops growing, the leaves become sickly and yellowish, and 
in the last stages the phylloxera disappears altogether from the 
decomposed and rotting roots, and the cause of death is obscure 
to one not familiar with the insect. Many cases of death ascribed 
to drought, overbearing, winterkilling, etc., are undoubtedly due 
to the presence of the root louse. 
“The abundance of galls on the leaves is not an indication 
of the presence of the rootlouse in any numbers, but, in fact, 
the reverse of this is usually true; while on the other hand the 
Fic. 143b—a, root galls; b, enlargement Fic. 144a—a, sexed stage, larviform 
of same showing disposition of lice; female, the dark-colored area indi- 
c, root-gall louse—much enlarged. cating the single egg; b, egg; c, 
After Marlatt, Div. of Bxtomology, shriveled female after Oviposition; 
Dep. of Agriculture. d, foot of same; e, rudimentary 
and functionless mouth-parts. 
After Marlatt, Div. of Entomol- 
ogy, Dep. of Agriculture. 
destructive abundance of the lice on the roots is often, if not 
usually, accompanied by little, if any appearance of the leaf form. 
This is particularly noticeable with the European grapes, which 
are very susceptible to phylloxera and rapidly succumb to it, yet 
rarely show leaf galls. American grapes, on the contrary, are 
generally very resistant-to the root form, and yet_are especially 
subject to the leaf-gall insect. Certain varieties, as the Clinton, 
which are most resistant to the former, are especially subject 
to the latter. 
“Distribution. The phylloxera was carried to France about 
1859, on rooted American vines, and has since spread through 
= ieee 
