But how many people have ever seen their larva?
Below is a rat-tailed maggot... larva of one of the larger groups of hoverflies, the Eristalinae. This fellow had established himself in our compost bin and was quite happy to turn our waste veggies into hoverfly material until I tipped him onto the compost heap out back.
That long bit sticking out the back (the 'rat tail') is a breathing tube allowing the maggot to live in waterlogged sewage, in temporary ponds, or in any environment with lots of water and lots of organic material. I'm guessing this is a sign I need to empty the compost more frequently, though on the flip side, I can think of no better fly to be chowing down on our leftovers.
Incidentally, the fly pictured at top, Episyrphus balteatus, doesn't produce rat-tailed maggots... its larva are one of the few active, predatory fly larva and look something like small green slugs. They feed on aphids and can be found, with some careful searching, on garden plants that have been aphid infested.
