What two spiders most likely bred to make the brown widow?

Question

What two spiders most likely bred to make the brown widow?

Answer 1

Male and Female Brown widows?  

Breeding two separate species will not produce a new species. It most likely won't produce anything.

Answer 2

well apart from the brown widow there's a red widow too...

also the northern black widow and  southern black too! :)  i think they got about a bit hey