200 PLANT LICE. 
from some other plant, presumably developing with the migrating 
viviparous females, who gave birth to the oviparous form. 
Myzus persice-niger E. A. Smith. (The Black Peach-louse). 
This plant-louse (Fig. 158) is exceedingly injurious in some 
of the peach-growing regions of the United States, but of course 
is not found in Minnesota, hence it is not necessary to describe it. 
The genus Nectarophora also contains a number of destruc- 
tive species, a few of which will be mentioned. In this genus 
the feelers are nearly always longer than the body and are situ- 
ated on distinct and approximate frontal tubercles; the seventh 
joint is mostly longer than the third. The wings are large, the 
legs long and slender; the long honey-tubes are cylindrical. 
Fic. 158—Myzus persice-niger D. A. Smith—Winged viviparous female. Atter 
Smith. (See also fig. 138). 
Plant-lice belonging to this genus are found on a number 
of wild and cultivated plants, sometimes in sufficient numbers to 
cause injury. ‘The grape-vine is sometimes invaded, nor do such 
other plants as the rose, blackberry, strawberry, pea, lettuce, and 
many others escape their invasions. Only a few can be described. 
Nectarophora viticola Thos. (The Grape-inhabiting Aphis). 
“About the 25th of June they first began to appear on the 
ends of the Clinton grape-vines, at first working only a few inches 
down from the end. They spread over the twigs rather rapidly, 
so that in the course of two or three days they were on a dozen 
or more. By this time the larva of a Syrphus and a Chrysopa 
had found them, and were at work upon them. By July toth 
the lice had spread over the vines along one side of a walk, which 
