thin spider web on my orchids

[rbarata]

Originally Posted by Orchidtinkerer

you have spider mites.
Sometimes they can be too small to spot with the naked eye but I can see the damage to the leaves and tiny black droppings too.

I also though about that but inside a terrarium with a humidifier that probability is low.
What are the humidity values?
That plant is inside the terrarium for how long?