"The Redback spider (Latrodectus hasselti) is a potentially dangerous spider native to Australia that resembles a Black widow spider. It is a member of the genus Latrodectus or the widow family of spiders, which are found throughout the world. The female is easily recognisable by its black body with prominent red stripe on its abdomen. Females have a body length of about a centimetre while the male is smaller, being only 3 to 4 millimetres long. The Redback spider is one of few arachnids which display sexual cannibalism while mating."
https://en.wikipedia.org/wiki/Redback_spider
Black widow spider may refer to:
* Western black widow or Latrodectus hesperus
* Southern black widow or Latrodectus mactans
* Northern black widow or Latrodectus variolus
* European black widow or Latrodectus tredecimguttatus
* Redback spider or black widow, Latrodectus hasselti
* Katipo or black widow, Latrodectus katipo
https://en.wikipedia.org/wiki/Black_widow_spider
"Latrodectus hesperus, the Western black widow spider or Western widow, is a highly venomous spider species found in western regions of the United States of America. The female's body is 14–16 millimeters in length and is black, often with an hourglass shaped red mark on the lower abdomen. The male of the species is around half this size and generally a tan color with lighter striping on the abdomen. The population was previously described as a subspecies of Latrodectus mactans and it is closely related to the northern species Latrodectus variolus. The species, as with others of the genus, build irregular webs, the strands of which are very strong.
The female's consumption of the male after courtship, a cannabilistic and suicidal behaviour observed in Latrodectus hasseltii (Australia's redback),[2] is rare in this species."
https://en.wikipedia.org/wiki/Western_black_widow
So the australian branch of the family are smaller and nastier to each other than their American cousins.
"L. tredecimguttatus is black in color, similar to most other widow species, and is identified by the thirteen spots which are found on its dorsal abdomen (the species name is Latin for "thirteen spots"). These spots are usually red in colour, but may also be yellow or orange. It is otherwise similar to other species in the genus Latrodectus."
https://en.wikipedia.org/wiki/European_black_widow
And the European branch of the family have spots instead of an hourglass for their pattern.
