User blog comment:StealthSimmons/I hate being a completionist/@comment-24021074-20140308204759

For Glowing Snail do a glowing mushroom biome on the ground, not underground, helps a lot. Running back and forth places is good option, when your screen doesn't see somewhere, there's possibility to spawn creatures now. (But make sure you do not run too fast, 'cause then there's no time for creatures to spawn.)

On my world atleast Tree Nymph Butterfly likes Living Trees ^^ (have found many near those trees)

'Gotta catch them all!