Crab spiders are ambush hunters that often attack pollinators at flowers. The unfortunate victim in this case, a fly, was likely looking for a meal of its own from the Arrowleaf Balsamroot. Sometimes the first sign that a crab spider is around is finding an insect in an unusual position, especially if the spider is colored to match the background. Not all crab spiders hang out on flowers. Species in the genera Bassaniana and Xysticus are often found on tree bark or the ground.
Crab spiders in the genus Mecaphesa are often “hairy” and their anterior lateral eyes are a little larger than the anterior median eyes. Only six of the eight eyes are visible when viewing the spider from the front and a little above.
Size: Length (not including legs): about ¼ inch (females); males are slightly smaller
Photo by: Glenn Marangelo on 5/22/22 near Missoula, MT