I have been finding various species of Minute Tree Fungus Beetles (family Ciidae) for several months now, but I've never found anything I suspected was one of their larvae. Till now, that is!
I figured even though the dark-bodied adults were easy to spot, tiny ciid larvae would be easy to miss in the light-colored flesh of tree fungus, and that may very well be why I never saw them. Nearly the opposite problem, visible larvae and invisible adults, is what I encountered in the present case.
I easily spotted these tiny white larvae in the dark brown interior of a species of peculiar-looking aged shelf fungi:
As I examined one larva in its burrow, I glimpsed a shiny, rounded surface, rich tan in color, that looked like an adult insect part. I pried into the tough, dry fungus grain and was able to tease out what had caught my eye -- the back end of a ciid adult
in its burrow. Its front end was attached and it was very much alive. This was a discovery for me. The tree fungus refered to in the ciid family common name is not thick, wood-hard shelf fungi so far as I know, but small, thin, ruffly fungi about silver dollar size.
Prying further, I collected more ciid adults and spotted their tell-tale burrows --- somewhat larger than those of these larvae.
I cannot conclusively state that these are ciid larvae, but the adult ciid presence makes me think they are. The size is about right as well, assuming they foreshorten on pupation.