A gooey looking transparent insect, when I encontered it last year I thought it could be the larva of a either a fly or a neuroptera, after a bit of research it turns to be the larva of a crane fly, prior tipulid and now placed in it’s own family, Limoniidae.
The majority of species in this family have aquatic larvae, and only three recent papers makes observations of larvae living in terrestrial habitat surrounded by a mass of jelly. These observations were all very similar and on species of the same genus, Geranomyia, in Costa Rica and the Fiji, I believe this one is also Geranomyia.
Diptera larva on a mass of jelly
The jelly helps protecting the larva against dehydratation, making it basically an aquatic-in-terrestrial kind of habitat, It’s thought to feed on organic matter over the leaves surface, and maybe on epyphites as well.
Probably these larvae aren’t rare and I encountered a couple of them while following a water stream through a very preserved rainforest area, I imagine just not enough dipterologists willing to assess their behavior came across them.
Head close-up of the possible Geranomyia larva in jelly, looking this close it resembles very much a caterpillar
Atlantic forest habitat were it was found, in SE Brazil
The pictures of the larva were taken during daytime, with a non-diffused slave flash placed at the left side of the subject. I tried with the flash behind the leaf as well, expecting a cool effect, but the lack if speculars caused by this angle just made the jelly surround the larva less visible.