You remember that old song we used to sing on school field trips or at summer camp—“The ants go marching one by one....” The chorus ends: “And they all go marching down—to the ground—to get out—of the rain—boom boom boom.” As in many fairy tales and childhood songs, there is a kernel of truth in that verse: Rainy weather does send ants scurrying, long columns of them rushing here and there, searching for any crack or crevice that will take them out of the drowning wetness, into someplace warm and dry. Our Sacramento pest control company recently got a frantic call from a woman who had put off dealing with an enormous ant infestation on a large crepe myrtle tree that hung over her drivewa