How do I Spawn different Enemies each Wave

Hi guys
(Sorry for my English)
So if i have a family with 3 objects in it lets say : Skeleton,Zombie and Witch.
And i want in my first wave to spawn 10 skeletons
on next wave to increase number of enemies so its gona be 10Skeletons and few zombies cos they are harder to kill
and so on increase enemies count every wave and the number of every enemie from easy to harder.
Thank you.

You don't spawn the "family", you spawn the sprites from it.
I guess you know you have to add a global variable called "wave" and increase it after each level.
At the start of the wave, you spawn a different number of enemies of each different kind. Use the "?" operator if you want to keep your number of events low.
You could also spawn some of them "off screen", to made them gradually appear.

Another approach is putting the sprites in the screen, each one with a "level" instance variable on it. Make all sprites "invisible" and, at the beginning of each wave, make "visible" the sprites with sprite.level<=currentlevel, and "destroy" every other sprite. But I think it is harder to implement.