Patience, Kilby.  The beetles are spending their time having mad passionate sex and laying eggs.  It will take months before the eggs hatch and the resulting "baby worms" grow large enough for you to be able to find them.  They're very tiny.  I started last fall with leftover mealworms from my daughter's science experiment, they turned into pupae, took them weeks to turn into beetles, and months before I finally found new little larvae.  
The life cycle clearly can take up to a year, and if you raise them at room temperature (68 degrees at my house) it goes slower. They like it warmer than that, but if I keep my house that hot I won't be able to sleep!
Remember, eggs hatch into mealworms, mealworms take a while to grow bigger, then turn into pupae, the pupae eventually turn into beetles, (but in the process they look dead).  Then the beetles have sex and lay eggs and we start over. 
Also remember, the eggs don't always hatch on the same day.  Eggs get laid as long as the beetles live, which can be several months, so every day is hatch day, and you won't be able to enjoy it without a dissecting microscope and a lot of patience.
I have fewer beetles now, my chicks have been playing beetle tag!