Agelena opulenta (Agelenidae) [Japanese name : ko kusa-gumo]
The spider is seen in many places from houses to in the mountains.
On trees, in hedges, on grass and in leafage of gardens, the spiders weaves
a platform web, or like a spider's house with terraces. There is a house
type with a funnel in the back of the web and the spider is waiting for its
prey in the entrance of the funnel.
See the photograph of the bottom. It's a mating pair of funnel web spiders.
The upper one is the male.
The length is 10-12mm.
It is found throughout Japan.