Could anyone suggest what this retreat might belong to? It was about 5 cm long, 1 cm wide at the entrance and positioned above a Lasius flavus nest. As well as soil from the nest, it had several dead ants incorporated into it. It seems to match the general description for Achaearanea riparia, but I don't know if anything else makes a similar structure? When I found it (18.9.12) it was occupied by a female spider and several young: I haven't been able to get a decent photo of them because of their size, but they did have the high abdomen which is apparently typical of the genus. Any thoughts much appreciated.