It could be thrips. What is that whitish spot on it closer to the bottom of the pitcher? Could it be scale? I'm wondering why your pitcher are underdeveloped. All these pests can cause that. I would look at the plant very closely and inspect it...even take it out and check the rhizome if you have to for mealy bug infestation. Just a suggestion. There's some reason why your pitcher are underdeveloped.
Do you know what kind you have? I see it just says sarracenia, not labeled. Do you keep the inside or out? Just asking cause these look like you keep them inside. I just love carnivorous plants and am curious about how people so different things to grow them.