These grow in acid bogs in the US. Such an environment is very short on nutrients, expecially nitrogen, and plants have developed all sorts of ways to supplement their diet with small invertebrates. Sarracenia leaves are rolled into a trumpet shape; the upper part produces nectar to attract insects. Just inside the lip, where the plant produces the most nectar, is a very smooth area with no hairs; the insect can't get a secure gip, and falls. Further down, all the hairs point downward, making it hard for the victim to go in any other direction. Eventually, it falls into the liquid at the bottom, which contains a wetting agent, and soon drowns. It rots, and the plant absorbs the resulting soup.
This is Sarracenia flava, the largest species. These pitchers are about fifteen inches high, and well over an inch across; other strains get significantly bigger. They look as though they could probably eat a blubottle or a wasp, but most of their diet seems to be small flies about the size of an aphid.
Sarracenia rubra rubra is the smallest member of the genus, barely reaching a foot high; the pitchers are about half an inch in diameter.
Meanwhile, the bees are flourishing, and beginning to store honey for me. I'm struggling to fins space for everything I need to plant out, as a lot of the plot is still a mass of weeds from last year. I can't go fast enough, that's my problem!