I ordered this wonderful plant from a merchant on Amazon. When it arrived it had three small traps growing. Now it has 8 large traps and more are popping up. Below is some info I found on Wikipedia.
the yellow pitcher plant traps insects using a rolled leaf, which in this species is a vibrant yellow in color, and up to over a meter in height (although 50 cm is more typical). The uppermost part of the leaf is flared into a lid (the operculum), which prevents excess rain from entering the pitcher and diluting the digestive secretions within. The upper regions of the pitcher are covered in short, stiff, downwards-pointing hairs, which serve to guide insects alighting on the upper portions of the leaf towards the opening of the pitcher tube. The upper regions are also brightly patterned with flower-like anthocyanin markings, particularly in the varieties S. flava var. rugelii and S. flava var. ornata: these markings also serve to attract insect prey. The opening of the pitcher tube is retroflexed into a 'nectar roll' or peristome, whose surface is studded with nectar-secreting glands. The nectar contains not only sugars, but also the alkaloid coniine (a toxin also found in hemlock), which probably intoxicates the prey. Prey entering the tube find that their footing is made extremely uncertain by the smooth, waxy secretions found on the surfaces of the upper portion of the tube. Insects losing their footing on this surface plummet to the bottom of the tube, where a combination of digestive fluid, wetting agents and inward-pointing hairs prevent their escape. Some large insects (such as wasps) have been reported to escape from the pitchers on occasion, by chewing their way out through the wall of the tube.