Moths.

Blance DuBois is a moth. At least, that is what Tennessee Williams implies when he comments that "there is something about her uncertain manner, as well as her white clothes, that suggests a moth" in A Streetcar Named Desire. When I first read that specific line in the play, I passed over it. Yes, I passed over such strong, profound symbolism in my hurry to get to the actual "action" of the play. But in retrospect, the beauty of Streetcar is not in the actual plot of the play, but in the symbolism that it contains. No, I'm not criticizing the play's plot line in any way, but I just find the fact that white is referenced multiple times throughout the language of the play to represent innocence, that music swells and fades at the appropriate times, and that Blanche DuBois, prim and naive (on the outside, at least) is compared to a moth.
Moths are interesting creatures. Constantly attracted to light, they never seem to be satisfied with their place. After having found a spot near the light, they often spontaneously fly to another spot. Only to do the same spot-hopping once more. All night. And yet, while being attracted to light, they can never seem to stand being in the bright light for more than a few moments at a time before flying off to find another spot, another light. Moths do not usually have a positive connotation either. Unlike their more beautiful, elegant counterparts, butterflies, moths do not fly beautifully around flowers. No, they reveal themselves at night, and become a nuisance to late-night backyard chats as they zigzag around any and all light sources. Moths are pests. They can destroy large expanses of fruit orchards, can eat away at beautiful flowers.
Blanche DuBois is compared to a moth. And I can totally see it. Like a moth, she is attracted to light. Fervently. Whenever she sees any relation to light, she quickly latches onto it and attempts to showcase herself in the light. She relates light to white, to innocence. And Blanche desperately desires to be innocent. Or, at least perceived as innocent. She wears white frequently to "symbolize" her innocence. She explicitly states that her astrological sign is Virgo: the virgin. And while her attempts at being perceived as innocent seem blatantly obvious to me, she seems to be utterly unaware of her obvious attempts.
Blanche ultimately fails at being perceived as innocent. Once Stanley finds out about her past, her cover is blown, and his intuitions about her are confirmed. Mitch realizes that he has never seen her in the light and removes the paper lantern from the light. Blanche the moth is revealed. Although I cannot say that Blanche is corrupt or completely delusional, I must say that she is not innocent. She does have problems with reality and fantasy, as evidenced by her actions and thoughts, it may be because of her moth-like qualities. She may be blinded by reality. Or fantasy. Or both.