Complex sentence: Aphids occur as small soft bodied insects on the underside of leaves and/or stems of the plant; usually green or yellow in color, but may be pink, brown, red or black depending on species and host plant.
Split into simpler sentences: Aphids occur as small, soft-bodied insects on the underside of leaves and/or stems of the plant. They are usually green or yellow in color, but may be pink, brown, red, or black depending on species and host plant.