Strange bees or late small swarm?

[qa33010]

We came home today from the store and I noticed I needed to go and check on my one and only colony.  There was a ruckus on the milk crate in front of the hive and some dead bees.  I also noticed dead bees in my bucket of water that I keep out for them.  They were not my bees in the water and about three of my bees and six of my neighbor's bees were dead and about forty of the other bees.  Some were smaller than my bees and mine are smaller than my neighbors package bees.  Also some were black and mostly black.  But the one thing that was strange was the other bees were speckled with a white color powder or small crystal-like flecks.  When I first showed up there were about a tennis ball size group of bees on the crate.  Mine didn't care about me but these others kept buzzing me.  My girls were also on high alert at the door so
I put up the robber screen.  
I have some pix and if I get them developed I'll try and post them.

One of them did zap me when I slapped at a mosquito on my leg and she fell off my leg and into my shoe (what I get for not suiting up).  I also saw what I thought was a drone, but didn't look stubby and rounded enough, land and head straight into the hive without more than a sniff from the guards.  

Do I need to be worried about what may have been on the strange bees?  Could they have been a swarm trying to take over?  I did see in the ball, as I moved them apart, a small dark bee with a black shine thorax that the others didn't have.  Could they have been run out of their hive and looking for a new home?  Thanks for your time!  David

[stilllearning]

"" But the one thing that was strange was the other bees were speckled with a white color powder or small crystal-like flecks. ""

DID THIS POWER FALL OFF LIKE THEY HAD BEEN SPRAYED WITH SOME CHEMICAL    IS THERE ANY ODOR TO THE POWDER

[newbee101]

Is this what your talking about?
I have no Idea what it is. It was all over the bee

[qa33010]

I didn't smell anything but it is hard to discribe.  If I can get a corpse or if they are still there tomorrow I'll try and get a better idea what it is.

[Joseph Clemens]

Sure looks like it could be pollen, or even powdered sugar.

[Apis629]

This may be a little "far-out there" but, I know that some orchids will actually sitck their pollen with a resin to the head or thorax of an insect.  I'm not sure if honeybees ever pollenate orchids so, I could very well be wrong.