PLANT LICE. 191 
When the latter developed wings they were transferred to cov- 
ered branches of Waahoo. Here they deposited the last brood 
of wingless females. As soon as the males could be obtained 
they were transferred to the nets on Waahoo. By October 12th 
eggs were found around the buds of the covered branches. 
“The following conclusions can be drawn from the work 
as done: 
“First.—That Aphis rumicis and Aphis euonymi are one and the 
same. 
“Second.—That this Aphis has a true migration twice a year, 
first from Waahoo to annual weeds from May 23d to June 
,loth; and second back again to Waahoo from September 
15th to October 15th, to deposit their eggs around the 
buds. 
“Third—That it can live and feed on the Snowball. In fact 
quite a number of colonies, being deposited by late migra- 
tions, were observed the present fall on Snowball leaves 
after the Waahoo leaves had fallen. This habit of also 
migrating to the Snowball and infesting the flower clus- 
ters, as proven by experiment, accounts for Buckton’s 
mixed descriptions of the different forms of Aphis viburm, 
and his statement that it curls the leaves and infests the 
flower clusters. In fact what was supposed to be Aplus 
viburni has not been found on any place except the curled 
leaves. The most characteristic difference between the 
two species is to be seen in the larval forms; those of the 
Wahoo louse being an olive brown color, while those of 
Aphis viburni are greenish white. 
“Fourth—That Aphis viburmi does not migrate to such weeds 
as Shepherd’s Purse and Dock. Though by June 15th all 
had left the Snowball leaves and were not seen again until 
the latter part of October.” 
Knowing that some plant-lice migrate to weeds, which have 
no place in the garden anyway, these should be sprayed with a 
strong emulsion and then plowed. In this way the large ma- 
jority of the insects would be destroyed and could not later in- 
vade useful plants. 
