Mealworms are an excellent part of a varied diet for many reptiles and amphibians and are probably one of the most commonly used prey item next to crickets.  You can purchase mealworms from your local pet store or even bait shop, order them online or even raise your own colony.

They are scientifically known as Tenebrio molitor and are the larval stage of this particular beetle.   As with several other worm species, mealworms have four life stages:

1. Egg (about 1/20th of an inch in size)
2. Larva (this is the worm used as your food source)
3. Pupa (looks like an alien out of a science-fiction movie)
4. Beetles (these are what breed and lay the eggs)

Mealworms will reach a maximum length of roughly one inch after molting approximately 5 times.