PLANT LICE
the winter eggs. The eggs are again collected by the ants and carried to safety for the winter into the depths of their underground abodes. All this the ants do for the aphids in exchange for the honey dew they receive from them. The ants have so domesticated these corn-root aphids that the aphids would perish without their care. The farmer, therefore, who would rid his cornfield of the aphid pest, proceeds with extermination measures against the ants.
The crowded aphid colonies exposed on stems and leaves naturally form the happy hunting grounds for a
Fig. 102. A common ladybird beetle, Coccinella novemnotata, that feeds on aphids. (Enlarged 5 times)
A, the larva. B, the adult beetle
host of predacious insects. Here are thousands of soft- bodied creatures, all herded together, and each tethered to one spot by the bristles of its beak thrust deep into the tissues of the plant—a pot-hunter's paradise, trulv. Consequently, the placid lives of the aphids have many interruptions, and vast numbers of the succulent creatures serve only as half-way stages in the food cycle of some other insect. The aphids have small powers of active
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