I was just outside checking my pond and doing my usual observations when I heard this loud buzz/squawk - sounding like the noise locusts make. I looked up and saw 2 BIG orange dragon flies - flying mid-air, one wason top of the other one backwards. Then they seperated and the smaller of the 2 went to the water and aggressively splashed its butt along the surface. I watched this for a good 5 minutes. Meanwhile the bigger dragon fly was hovering around.

Was this mating? Was the dragon fly dragging its butt in the water - the female laying eggs?

You got it! Dragonflies mate in the air in tandem flying around. The female dips her tail into the pond, usually over things like lily pads, and deposits her eggs. While she does this, the male may stick around to chase off other male suitors. Orange dragonflies - sounds like they were pretty!

We've had what appears to be the same orange dragon fly hanging out near our pond for over month now. It is not at all afraid, and lets me take very close pictures. Sometimes there are two, and sometimes others show up and get chased away. Once the dragon fly chased off a humming bird! Most of the dragon flies I see are orange, but once I saw a really huge green one land on some floating plants and stick its abdomen into the water. Perhaps it was laying eggs, but it didn't do the flying dipper thing that the orange ones do. It was really scary looking -- I was glad the orange one chased it away.

Now a question: The guy who built our pond said that dragon fly larvae need several inches of muck in the bottom of a pond to live in. Our pond is new and has no muck at all in the bottom, so I was surprised to see dragon flies laying their eggs in an unsuitable environment. Even though the larvae can be agressive predators, I love dragon flies and would be happy if these eggs would hatch and the larvae would survive. Is it true that they need mucky conditions?

That sounds it would be cool to watch:)

Don't worry, your pond will soon have some muck somewhere. As long as they have food, dragonfly larvae/nymps/naiads can live even on a bare liner. They of course want to remain inconspicous so they don't get eaten and also to be stealthy to catch their prey so they will find the most gunky place to hide so no one can see them. If there's not enough slop in your pond, they may be easily found and eaten by any fish or other aquatic animals. They would also be less likely to find and capture prey. So, a little bit of pond debris is good but you really don't want too much either as then the water quality and animal life suffer. The dragonfly mothers are thinking ahead to when the pond will be a bit more mature and great for their young.