Insect and Spider Identification: something like a black widow or a red back , 1 by bokisan

bokisan wrote:
the three species of black widow in north america, have a progression to black in stages, as they molt. with each new exoskeleton, they lose some of the red on their backs

young females, as their bodies turn black, will still show this line of dots, and diminished line,
... then on down to one red dot, and then only the red under the belly.

if she lives long enough she will lose the red hourglass, as well

you can see, in this photograph of uma, ... she has lost all but her last red dot remaining on her back,
right down by her spinneret,