5. Northern Yellow Sac Spiders The northern yellow sac spider (Cheiracanthium mildei) is a small spider that commonly inhabits many parts of the world, including North America, Europe, and Asia ...

They have black bodies with patches of yellow, white, or orange on top. Their mouth parts, chelicerae, are iridescent green. You'll find these tiny arachnids during the day on window sills and decks.