DrSpunj
Explorer
During this week's session the mages our party was fighting used (presumably) Summon Monster to sick half a dozen Apes on us. We took out the head mage and eventually his flunkies as well. A couple of the Apes were the last to fall. At the end of the evening we started wondering whether the Apes should've disappeared when their caster was laid low. I've just looked through a bit of PHB in the dying/death and spell durations sections and couldn't find anything on the subject, nor could I find any help in the SRD or FAQ.
Can someone please point out what I missed?
Or are the rules here ambiguous and therefore up to the DM?
I did find the rules about any spells the Summoned creatures cast end when they're time is up, but that wasn't that helpful
Thanks ahead of time.
DrSpunj
Can someone please point out what I missed?

I did find the rules about any spells the Summoned creatures cast end when they're time is up, but that wasn't that helpful

Thanks ahead of time.
DrSpunj