What exactly did Hercules mistake Megara and his children for as he slew them?

I read somewhere that in his fit of delusional madness Hercules mistook his wife Megara and children for monsters /enemies. But What exactly did Hercules mistake Megara and his children for as he slew them?
Are there any details in any plays or stories ?

First post on the new boards! (I think).
Anyway, Heracles was deliberately misled (I think by Hera) to perceive his kids as the kids of Evristheas and that is the reason he wanted to kill them. I do not know why he hated Evristheas. Some versions of the myth have him killing his wife, some do not. and some have her escaping or Heracles coming to his senses before killing her.

Evristheas, Heracles’s mortal enemy. That was the missing piece of the puzzle. Thanks half-elf.

Heh, don’t thank me, thank Wikipedia!

Wait. Heracles or Hercules?

Modhat: As this appears to have been answered, I moved it over to The Cafe for any further discussion.

Heracles would be the more proper way to say it - it means something like ‘devoted to Hera’ or ‘in praise of Hera,’ I forget what exactly. It was supposed to have mollified the goddess a bit, and of course did not work at all.

I think Hercules is the Romanization. Romantification?