1914] Natural Control of Toxoptera. 79 
graminum seeking shelter in the depths of the grass roots. They 
were found in this situation in South Africa in many cases all 
through the summer, probably thus obtaining some protection 
from the hot rays of the sun. The forms on the roots were 
quite white but when such were removed to wheat plants in 
the Insectary, either they or their off-spring assumed their 
natural color and it was found that the colonies on the roots 
tended by the ants consisted of both Toxoptera graminum and 
also Aphis maidis. These two species were also frequently 
found associated upon the summer grasses, especially Panicum 
laevifolium, Indian Corn, and Kaffir Corn. 
As to the rate of reproduction of Toxoptera in South Africa, 
it might be stated that it is about the same as it is in the United 
States. In South Africa, migrations over large areas as re- 
ported in the United States, are not so apt to occur. Similar 
migrations on a smaller scale, however, do occur. Usually, it 
is from the dryer portions to the wetter portions of the country, 
inasmuch as Toxoptera will kill the grain sooner, under dry 
conditions. There have been no reports of extensive migra- 
tions in the Transvaal but they are known in the eastern 
districts of the Orange Free State. Farmers about Ficksburg, 
O. F. S., state that the swarms occur coming from the west late 
in September or October. As the natives of Basutoland do 
not raise grain for green forage crops, and as the grass is always 
dead long before the winter grain comes up, most of the Toxop- 
tera injuring the grain in Basutoland must come by migrations 
from the Orange Free State. It is difficult to get any definite 
data on this point from the natives but they seem to know that 
something of the sort occurs. 
In South Africa, two internal parasites have been found 
which are capable of breeding in Toxoptera. The first (Aphid- 
ius phorodontis (?) is commonly bred from Toxoptera in the 
field. Another species is Diaeretus rape and has been bred in 
the field from both the Cabbage Aphis (Aphis brassicze) and the 
Green Peach Aphis (Myzus persice), both occurring upon cab- 
bages but in the Insectary this species was also bred into 
Toxoptera. It is doubtful, however, whether this species 
would normally be found breeding in the field upon Toxoptera 
unless the grain field was quite close to a cabbage patch. Aphid- 
ius phorodontis has been bred from the Green Peach Aphis 
