Becareful what you wish for... When the insect lays the egg, insect and places the grass on top it will finish the job by eating away the top of the pitcher so it folds over. They can do a good job at damaging a nice sarra collection.
This photo is from wild plants in the sandhills ecoregion, NC. I would guess hymenopteran. I've seen Exyra larvae in traps before but do they cause stringy organic debris to accumulate this much?
Evidently this wasp is catching prey that will serve as food for its offspring and then sealing it to prevent other predators from catching its eggs. I agree with with ElGecko's assessment and would further venture say that it's a beneficial relationship between the sarras and the wasp in that the fecal matter from their larva and physical breakdown of prey probably benefit the plant while the wasp larva get protection and lodging from the plant.
The plant would probably get a lot more nutrition of the pitchers were open the full growing season than from a few trapped and paralyzed insects.
Guys, let these wasps live, I mean they are just as threatened as wild sars right? Whats one cheap flava to a threatened wild wasp?
Leaving them alone is the best advice I can give anyone especially if you are allergic!