Flies pollinate a few specialized flowers. The y are attracted to drab, colorless or green flowers that often emit a foul odor to lure them. Examples are dutchman's pipe and stapelia. Most of us know that birds, and particularly hummingbirds, prefer red and orange flowers that are tubular in shape. Flowers that are pollinated by birds generally lack a scent.
Examples are ocotillos, salvias, red yuccas and aloes.
Finally, an important group of pollinators that is often forgotten are bats. They, like the moths, are attracted to flowers that open as night. Examples of bat pollinated plants are saguaros and agaves.