We observed foraging behavior of the crab spider Misumenops asperatus Hentz in Princeton, MA. This spider is a classic sit-and-wait predator that can move among foraging patches scattered within its environment. In our study, patches were composed of stems of goldenrod (Solidago rugosa P. Mill.) that had different numbers of inflorescence plumes (our measure of patch quality), which potential insect prey visit. Spiders made foraging decisions in two distinct ways. First, they most often hunted on high quality patches. Second, spiders foraging on high quality patches remained on their patches longer than spiders on medium or low quality patches. It appears that M. asperatus is basing its foraging decisions at least in part on assessment of a parameter in its environment that may correlate with prey abundance, without directly assessing prey arrival rates. Based on these behavioral patterns, we suggest that this spider is following a fixed probability of moving rule in deciding when to leave a patch.