Female northern black widow spinnerets, SEM

Coloured scanning electron micrograph (SEM) of Northern black widow spider, female spinnerets (Latrodectus variolus). There are 3 pairs of spinnerets that secret silk through piriform gland spigots. This venomous spider is found throughout the eastern US, from southern Canada to Florida, and west to eastern Texas. The female has the typical black widow red hourglass-shape mark on the underside of her abdomen. The marking is incomplete or split in the middle. Northern black widows also have a series of red spots along the dorsal midline of the abdomen, and many have a series of lateral white stripes on the abdomen. The female black widow is dangerous to humans, as her bite contains a significant amount of nerve toxin (neurotoxin, latrotoxin). This neurotoxin causes pain and swelling, and in rare cases, may even be fatal. The genus gets its name from the female's practice of devouring the male after mating. Magnification: x35 when shortest axis printed