Hi Bramblebee:
I know just how you feel it happened to me last year. Your Queen probally died, this happend quit often and as the brood dies off there is none to replace them. The ants came after the hive was so week they couldn't defend it. This is what I did this year and it worked for me.
Retrive your honey and place in a cool dry area, if you have any empty frames in the brood box save them and the ones that have something in them (anything) remove the comb replace with new foundation. Replace the bees in the spring and as always you will have to feed the new bees, give them some of the honey in the brood box but also feed the proper sugar mix. The most important thing to do is check for that queen, I know she is hard to see so look for eggs, if you see eggs, she was there in the last two days. This year I checked mine at least every 3 weeks (normal life cycle of the worker bee) that way if she is not there you have time to requeen. Another thing I did I started feeding my bees in Oct even though they had a good bit of honey, now it is paying off the hive is still strong dispite having a poor fall and relative hard winter.
Don't forget to come here and ask any question no matter how simple you may think it is, there are real professionals that read this forum regually and are more than willing to help.

Barnabus

thanks for the kind and thorough response Barnabus--most appreciated--BB

If you still have dead bees, you should package them up properly (paper, not plastic) and send them to the beltsville lab.

Any diagnosis based on your descriptions is pure guesswork and worth squat.

The free analysis will help you determine the cause of the die off, particularly if it was tracheal mites.

Most beekeepers don't bother, and choose a cause out of thin air. It doesn't really help them to misdiagnose the cause.

Thanks for the Beltsville tip:

When a hive is queenless the next vision is a great number of drones.
Why don´t you read to George Imirie, master beekeeper? Read, and re-read, you can find his writings at the web. He repeats many ideas every year, but I am sure that, we, the beehavers, are hard to learn.

I had a very healthy hive, both hive bodies full of honey for the winter.
I gave them menthol and apivar and closed up the hive. I came back the next weekend and 3/4 of the bees were outside dead in a pile on side of hive and the whole bottom hive body was uncapped and honey was gone? Any ideas? I've never seen this.
Zone 5