134 
This little fellow goes about getting its meals in a very quiet, 
unobtrusive sort of way. It crawls quietly up among a number of 
Toxoptera and the first one it touches becomes its victim. It at- 
taches its mouthparts to some joint of the legs, usually at the artic- 
ulation of the femur and tibia, and sucks out the juices of the 
aphidid. With a compound miscroscope the blood can readily be seen 
flowing in a constant stream, through the limb of the aphidid attacked, 
into the larva of the cecidomyiid. Rarely is the aphid disturbed 
and upon close observation the skin of the aphidid will be seen to 
Fig. 47.— Apliidolctcs sp., cecidomyiid fly whose larvse feed upon the spring grain-aphis. Greatly 
enlarged. (Original.) 
gradually shrivel up ; finally nothing but the empty skin remains and 
the larva crawls away in search of more aphidids, frequently with 
the old empty aphidid skin adhering to it. The time required to 
consume the juices of an aphidid varies with the size of the larva 
and of the aphidid. A larva that is about full grown can dispatch 
a small aphidid in a few minutes, while from 15 to 30 minutes are 
required for it to empty a full-grown one. These cecidomyiid larvae 
have enormous appetites and apparently keep up their work of 
destruction almost constantly until they become full grown. 
It is not at all impossible for this insect to become a very im- 
portant factor in the control of Toxoptera, as the adults are capable 
of flight and deposit large numbers of eggs. 
