There are three species of micrathena spiders in our state. All are orb weavers (they spin intricate, circular webs), and all have some combination of pointy, conical tubercles on their bodies. Because males are small and rarely seen, the following descriptions refer to females, which are commonly seen resting in their webs. All have glossy black legs.
M. gracilis, the spiny-bellied orb weaver or spined micrathena, has 5 pairs of black tubercles and a white and black (or yellowish and brown-black) mottled abdomen.
M. mitrata, the white micrathena, has 2 short pairs of tubercles and a white abdomen with a few distinct black blotches on the upper side.
M. sagittata, the arrow-shaped micrathena, has striking reddish, black, and yellow colors and has 3 pairs of tubercles. The pair of tubercles at the back end of the abdomen are rather large, forming two corners of the triangular (“arrow-shaped”) body.