Black widow spider egg (Latrodectus hesperus), SEM

Coloured scanning electron micrograph (SEM) of Western black widow spider egg (Latrodectus hesperus). Latrodectus hesperus is a venomous spider found in the western regions of North America usually in warmer climates. This spider can be identified as a female by the red hourglass-shape mark on the underside of her 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, although this behaviour is seen in other spiders. After the female and male mate, the female lays several bunches of egg sacs in the web, each containing about 750 eggs. Magnification: x29 when shortest axis printed at 25 millimetres.