80 Annals Entomological Society of America [Vol. VII, 
(Myzus persicez), the Black Peach Aphis (Aphis persice-niger), 
the Corn Leaf Aphis (Aphis maidis), Yellow Aphis on Milk- 
weed (Aphis nerii), a reed Aphis (Hyalopterus arundinis) and 
the Black Bean Aphis (Aphis rumicis). 
Aphidius phorodontis, however, seems to be capable of 
destroying just as many individuals of Toxoptera as is Aphid- 
ius testaceipes. The average period of development from egg 
to adult seems to be about ten to twenty days. The maximum 
number developed from one female was 286 which is only 15 
below the maximum obtained by Mr. Parks in the United 
States Department of Agriculture. It is safe to assume that 
in ‘‘stinging’’ so many that it must often occur that two or 
more eggs are laid in one individual Toxoptera so that it is safe 
to assume that Aphidius phorodontis lays 300 or 400 eggs. 
There seem to be about 70 per cent. of the parasites females if 
the mother Aphidius has been fertilized. It was also shown 
that one male would fertilize more than one female but time did 
not permit of finding how many females might be fertilized by 
one male. If the female was not fertilized, she would lay eggs 
and the proportion of the parthenogenetic off-spring were 
about 70 per cent. males. 
When an infested grain field is examined, even though 
species of Aphidius are present, one never finds a large number 
of parasitized forms of Toxoptera upon a weak plant such as is 
shown to be the case in the United States. Probably one 
wheat plant would, at the most, not have more than ten para- 
sitized forms upon it. Besides this species of Aphidius, there 
are three different species of ladybirds which play an important 
part in controlling Toxoptera in South Africa. The first and 
most important is the Black Spotted Ladybird (Adalia flavo- 
maculata), the Red Spotted Ladybird (Chilomenes lunatus), 
and the Black Ladybird (Exochomus nigromaculatus). These 
ladybirds are a most important factor in controlling Toxoptera. 
It is seldom that one finds a field badly infested in which lady- 
birds are not present and rapidly destroying Toxoptera. The 
life history of Adalia flavomaculata was worked out rather 
completely. 
Under favorable climatic conditions, the eggs hatched in from 
five to seven days from the time they were laid. The larve 
feed for a short time upon the eggshells but soon begin feeding 
