130 
THE SPRING GRAIN-APHIS OR 
in grain fields badly infested with plant-lice, and when quite num- 
erous attract attention by a buzzing noise made while in flight. The 
predaceous larvae are sluglike and of a dirty grayish or yellowish 
green color; this is the only stage in which they are destructive to 
Fig. 41.— The spotted lady-beetle (Megilla maculata), an enemy of the spring grain-aphis: a, Larva; b, 
empty pupa skin; c, adult. Enlarged. (From Chittenden.) 
plant-lice. Little is known of the life histories of these insects as 
very few careful rearings have been made. 
Syrphus americanus Wied. (fig. 43) and Eupeodes volucris O. S. 
(fig. 44) were by far the most numerous syrphids in the grain fields in 
the Southwest in 1 907. A field at 
Kingfisher, Okla., in April, 1907, 
literally swarmed with them; 20 
or more could be taken with each 
sweep of an insect net. A curious 
fact with reference to their occur- 
rence in such abundance in this 
field, however, was that Toxoptera 
was not present there in destruc- 
tive abundance, while the adjoin- 
ing field was suffering greatly from 
their attack, though, curiously 
enough, the syrphid flies did not 
appear to be so plentiful there. 
These two species were present, 
apparently, over the entire south- 
western area that suffered greatly from Toxoptera attack in 1907. 
Syrphus americanus was reared also from Toxoptera material sent in by 
Air. E. C. Haynsworth from Sumter, S. C. Prof. J. M. Aldrich states in 
his catalogue of North American Diptera that he reared Eupeodes 
volucris from Aphis avenx at Moscow, Idaho, Dr. C. V. Riley states, 
Fig. 42.— A South African lady-beetle, Adaliaflavo- 
maculata, which with its larva attacks the spring 
grain-aphis in the Orange Free State, South 
Africa. Enlarged. (Original.) 
