This is a HugeSpider with a narrow abdomen.
If you don't like the default texture, you can use a dark brown texture made by Yandros. The texture is also included in the package.
This can be used in Thief 1 (with a slight change to the new texture) or Thief 2
You can download the meshes by clicking Here
Narrow with default texture:
Dark brown skin:
There are installation instructions in the .zip.