Running Crab Spiders aren’t true crab spiders (Thomisidae family). For true crab spiders (look for one later in this report) you will notice that the front two pairs are longer than the rest. For this genus in particular, the second pair of legs are always longer than the 1st, 3rd, and 4th pair. Generally, runners are active hunters, chasing prey, while true crab spiders are ambush hunters. Look for these spiders running in spring and summer on branches and trunks of bushes and trees.They can be found at rest too, but their flat body and cryptic coloration make it challenging.There are 55 species in the U.S. and Canada and they are often difficult to identify.
Photo by Kristi DuBois on 3/28/20 in Missoula, MT