38 HOW TO TEACH BEETLES, BUGS, AND LOCUSTS. 
winged and the wingless. Most of the females are 
wingless and most of the males are winged, but there 
are wingless males and winged females. The sex 
may be determined by the size of the bodies, the 
males having much smaller bodies than the females. 
Plant-lice spend the winter in the egg; at least this 
is true of the majority. These eggs hatch in the 
spring, bringing forth wingless females. These 
produce large numbers of living females both with 
and without wings, and this goes on all summer. 
The last brood of the season are both males and 
females. The wonderful rapidity with which these 
creatures multiply makes it possible for a single pair 
of aphides to be the ancestors of many thousands of 
plant-lice in a single season. 
One of the most curious traits of these insects is 
their behavior towards ants. Any observer wiW. 
soon see ants creeping about wherever there are 
aphides. If watched, the ant will be seen to 
approach an aphis and touch the abdominal appen- 
