It sounds like they're probably maggots - the larval form of flies. If they're housefly maggots ... well, almost everyone dislikes houseflies, so you probably don't want to breed them. If they're black soldier flies (BSF) - well, there are differences of opinion about those here. BSF are powerful digesters of protein, and can reduce a lot of input to a little output fast. Some figure, hey, that's what composting is supposed to BE - various micro and macro digesters gobbling up the edible bits of kitchen and garden waste, and leaving behind organic material suitable for enhancing garden soil. Others point out that it is possible to prevent maggots in compost, and claim that their presence is proof that you've done something wrong. (I figure, IF you're trying to prevent having maggots and you have 'em, you've done something wrong. But if you are pleased by the BSF's digesting the material they digest, and not trying to prevent them, then you haven't done anything wrong.)

Should you want to exclude black soldier flies from your composting? Maybe. BSFs don't pester people in the way that houseflies do, so allowing them in your compost isn't going to cause problems for neighbors, etc. But - they do eat all your good compostable stuff and then fly away ... that is, instead of just converting compostables into stable compost (like fungi and bacteria do), they're partly converting it into black soldier flies, and when they fly off, all of the organic material they've incorporated into their bodies disappears with them. I think that's one part of why it seems like they can manage to reduce a pile so very dramatically (though many digesters do that, it sometimes seems the most dramatic with BSF maggots). So if your goal is as much compost as possible, you might want to avoid BSFs. If your goal is not sending lots of waste to a landfill, and you're looking for the easiest way to get it all decomposed, BSFs might be fine for you.

So - flies tend to be attracted to wet glop near the surface of compost. If you want to NOT have 'em, put dry stuff on top of your wet stuff. Getting rid of them after they're there is harder, but if you just make the pile not-attractive for flies laying eggs, the ones already there will become flies and fly away, and then you'll have a maggot-free pile again.

Maybe, possibly maggots, the larva of flies.
http://www.worsleyschool.net/science/files/maggot/info.html
or maybe, possibly grubs, the larva of beetles.
http://www.american-lawn/insects/grubs.html

lcpw gets a VoR* award.

Lloyd

*Voice of Reason

The Black Soldier Fly larvae are a valuable addition to your compost pile. The do not eat cellulose but rather process kitchen garbage, fish and mammal offal and animal manure into a friable compost that is also a viable food for composting worms. In the process, they innoculate their excrement with beneficial bacteria that's good for your soil and your compost pile. The cool thing for composters, assuming you have them in your pile, is that you can compost all the stuff you supposedly arent supposed to compost - meat, dairy, fats, etc. (mine even digest pure bacon drippings), and within hours convert it into BSF manure with none of the problems those things can typically cause with compost.

They secrete pheromones that repel houseflies. They do not sting (though they look like wasps), they have no mouths so the adult flies do not feed or swarm like houseflies. They are not vectors of disease. The larvae are high in calcium, proteins, fats, omega 3 fatty acids and make valuable suppliments to poultry or swine feed. The larvae make great fish bait, and they are much in demand as pet food for people who raise exotic reptiles and amphibians.

They process garbage, fish guts, and animal carrion so rapidly that it doesn't have time to become anaerobic and stink. Yes, they consume nitrogenous additions to your compost, but so do bacteria and earthworms. In fact, Black Soldier Flies make the job easier for bacteria and worms to do their jobs.

The only downside is they look kind of disgusting (until you get used to them). To a compost purist, perhaps their presence is a sign of "poor compost management", but it's a self-correcting thing that consumes the out-of-balance part of the equation. The end result is good compost when Black Soldier Flies are present.

Here is a link that might be useful: Raising Black Soldier Flies

WOW!! I think we just found an expert in BSFL!

It's going to take me a while to get through your website completely but from what I've read so far, I bow in the general direction of Florida.

Lloyd

P.S. and you win awards for brewing beer!!