PLANT LICE. 167 
the latter 1s most abundant. These are small pale yellow or 
whitish, covered at the posterior part with a mass of flocculent 
matter; their form is mostly pear-shaped, and they measure an 
eighth of an inch in length when full grown. 
The smaller rootlets of the beet are attacked first, and they 
are soon destroyed, the leaves in consequence wilt, and the whole 
beet becomes spongy. If we find any wilting leaves in our fields 
of sugar beets we had better investigate at once to discover 
whether this louse is present or not. It is of course always in- 
advisable to plant beets as a first crop on new land, nor should 
our farmers grow these plants, or any other root crop, year 
after year, in the same field. Here, again, proper and systematic 
rotation is all important. 
Fic. 147—Pemphigus bet#2 Doane.—a, winged female; b, wingless female; c, an- 
tenna of winged female. After Doane, 
Other lice, not discussed in this report, also infest the sugar 
beet. 
In the section Schizoneurini we have genera in which the 
third discoidal vein of the front wings is forked; the short feel- 
ers are six-jointed, annulated, and with transverse sensoria, or 
when not annulated with circular sensoria. The honey-tubes are 
rudimentary or wanting. 
The species either secrete a flocculent matter, or they are 
simply covered with a fine powder. Some form galls, but the 
majority simply curl the leaves and are protected by them and 
the flocculent exudation. A few species living underground also 
belong here. Some naturalists consider the Schizoneurini entitled 
