Identify insect larvae

LeadFarmer

I have an insect nest box that is partially occupied this summer, can anyone identify which insect larvae this is please..

Four of the smaller holes have been closed up with mud..




And inside are these little grubs...,

Alan Clark2 in Liverpool

Red Mason Bees use mud to seal the nest, which I suspect is what they are.

LeadFarmer

I have some mason bee cocoons from last year, waiting for them to hatch. But the holes in these tubes are much smaller, and the grubs are not in individual cells so I don't think they are mason bees.

Fire

No, not bees. Perhaps parasitic wasps, but I’m just guessing.