<P> Latrodectus is a genus of spiders in the family Theridiidae , most of which are commonly known as widow spiders . The genus contains 31 recognized species distributed worldwide , including the North American black widows ( L. mactans , L. hesperus , and L. variolus ) , the button spiders of Africa , and the Australian redback spider . Species vary widely in size . In most cases , the females are dark - coloured and readily identifiable by reddish markings on the abdomen , which are often ( but not always ) hourglass - shaped . </P>
<P> Latrodectus is a genus of spiders in the family Theridiidae , most of which are commonly known as widow spiders . The genus contains 31 recognized species distributed worldwide , including the North American black widows ( L. mactans , L. hesperus , and L. variolus ) , the button spiders of Africa , and the Australian redback spider . Species vary widely in size . In most cases , the females are dark - coloured and readily identifiable by reddish markings on the abdomen , which are often ( but not always ) hourglass - shaped . </P>
where is the red marking on a black widow
where is the red marking on a black widow
the abdomen
the abdomen