how to differentiate between laelia and cattleya

[weederwoman]

I have a number of unlabeled orchids in my care. At least two of them could be laelia species (old tags in a box). There are also a number of unlabeled plants that are most likely catt species or hybrids. The only old label I have for these is for empress bells, a famous old girl. The first plant is getting ready to bloom. One stalk has a cluster of four buds, another a cluster of three. I know there must be ways to tell laelias from catts, but my search in the forum didn't bring anything up. Any help on general rules? And I will post photos when the blooms open. Thanks