I started raising Mealworms a couple of months ago. I started with 1100 mealworms and had a couple of cleaner worms and beetles included. I have went through all the stages and now have thousands upon thousands of baby worms and eggs. But I have also come across 2 other types of worms in my bin since hatching. I have one kind that resembles a grubby worm like you would find in a leaf fold outside and they is in the crease of some carrots where they've made small nests. Some have turned into the same exact looking cocoon stage as mealworms,but much smaller. I do not have pictures of these. The other type resembles a mealworm, but is blackish instead. They are also 4 times or more bigger than the baby mealworms and they move fast. I have pictures to compare.