Crab spiders are quite common around here: Although I grew up thinking about spiders as spinning webs, catching prey in their web, the crab spiders behavior is different. These are predators, that lurk in flowers and foliage and just wait until an appropriate sized mean comes within range. They can then move remarkably rapidly, grabbing hold of their meal to be, injecting both a toxin that poisons and paralyzes the victim, as well as digestive enzymes that work more gradually but allow the spider to eventually extract nutrients from within the exoskeleton of the victim.

In the picture below, the white crab spider is eyeing this bee that has been feeding on this flower. In this case, the bee did not approach closely enough to be caught. 

However, not all are so lucky. This fall, I watched, as a crab spider grabbed a bumblebee that was substantially larger than the spider itself. The ensuing struggle was brief:

Crab spider catching a bumblebee

The bee twitched for about 15 to 30 seconds, while the pair hung suspended from a single strand of silk that the spider had released through its spinneret: Note how it is using a rear leg to position itself with the silk. The single strand was strong enough to hold the weight of both hunter and prey.

Crab spider and bumblebee suspended by a strand of silk

Within a minute, the spider had pulled its prey back up under the leaf, where the digestive process and subsequent consumption could take place:

Returned to the leaf to eat

This final step in the drama may take a day or more, and eventually the shrunken exoskeleton is dropped and the spider goes on to continue a new hunt.