This is from the natural history museum
What do false widow spiders look like?
All species have distinctive sets of markings on their abdomens: they have a narrow white or lighter band around the front of the abdomen towards their head, and also other markings that vary by species. However, all of these marks can be variable, faded, or missing, especially in adult females.
Females have a globular shiny abdomen, while male abdomens are smaller and less rounded, but are more clearly marked.
Their webs are a tangle of criss-cross threads which may become quite dense in the centre if left undisturbed.