[Buttons12]

Simple rule of being inside my house...
No legs, you die
Two legs uninvited, you will probably die
Four legs, depends on attitude but probably get released
More than four legs, you die
Outside the house it's live and let live; unless your attitude demands that you die.

This is the rule in my family, almost word for word. We are somewhat more stern about uninvited four-leggers. But unacceptability is basically in the leg count. Thus there are spiders that might be tolerated if they discouraged ants or beetles, but millipedes are intolerable no matter how many spiders they might kill.
We also have a special rule about winged creatures: wings count as legs.

[ETL]

That's Racist Species-ist!