Dustships started using hallromm butterflies as messengers long ago, but nowadays they are popular everywhere, especially after new breeds proved to be more cold resistant. They carry letters in strap-on belly bags, and in some places heavy in short range messages the air is fluttering with hallromms. The butterflies insist on their own bushes to which they return faithfully - dustships keep those on one of the floating rocks.
Hallromms enjoy having their bellies stroked, leave tiny marks on elvish skin, and are mildly intelligent, at least enough to play with the omnipresent bugfairies.
"The bugfairies have painted the hallromms again. One almost lost an antenna trying to clean itself, but washing isn't a solution either, I'll break them to pieces. I'd ask the fairies to fix it, but I'm scared of what they'll do - probably paint the original colours back or something."
— Hetcal, Lozirian
Originally hallromms (German: Hallrömm) were only found on dustships, but somehow a few years passed in Genius Loci while hallromms were around, and then they were popular on the ground as well. This is actually the first painting of them, I had just a few scribbles of their anatomy before.