84 Annals Entomological Society of America __[Vol. VII, 
If Adalia flavomaculata and Chilomenes lunatus are found 
there, it is very doubtful whether the value of Aphidius testa- 
ceipes will be as great as it is in the United States. 
The Little Black Ladybird, Exochomus nigro-fasciatus, is 
reported from the Soudan and it, no doubt, occurs in British 
East Africa. Several Aphid-eating Ladybirds have also been 
reported from the Soudan as being particularly beneficial in 
controlling an Aphid on Kaffir Corn. 
Another point in favor of the ladybirds is that they will 
breed and will control Toxoptera at a lower temperature than 
Aphidius. All the stages are greatly retarded, however, by 
cold and the adults do not seem to lay eggs. It seems from 
experiments carried out that more Aphids are required per 
ladybird in their lives when it is cold than is the case at a 
warmer temperature. Larve of Adalia lived for about thirty- 
five days at a mean daily temperature of from 45 to 55 degrees 
and ate during that time 416 Aphids per larva, as compared 
with 319 in the summer time in a period of thirteen days. At 
a lower temperature, therefore, the larva eats only about half 
the number of Aphids per day, but feeds for about 224 times as 
many days. 
Besides the ladybirds, one finds a Syrphid Fly (Xantho- 
gramma scutellare) does considerable good in controlling Tox- 
optera. The Syrphid also incidentally destroys Aphidius by 
destroying Toxoptera which contain the eggs or larve of 
Aphidius. In no case, however, were they found destroying 
the parasitized forms of Toxoptera. A leaf which has been 
cleaned by Syrphid Fly larva will be found to have a few 
parasitized forms of Toxoptera remaining on it. This, how- 
ever, would not be the case if the leaf had been cleaned by a 
ladybird or a ladybird’s larva. 
This Syrphid Fly is also retarded in its good work by a 
parasite Bassus laetatorius. This parasite very effectively 
controls the Syrphid Fly when the latter becomes very abund- 
ant in the field. The most beneficial work of this Syrphid 
was found to be in fields which were just becoming infested 
with Toxoptera migrating from some other place. This 
Syrphid seems to be the first to find the Aphids in their new 
home and commence the work of destruction, but as soon’as the 
