I cannot tell. Is that by her genitals? Rabbits have scent glands near their genitals that contain a dark, waxy substance under normal conditions. Here's some other info on those:
http://www.rabbitsonline.net/f22/scent-glands-49871/ It looks like it could be part of her scent glands but they've been chewed open a bit. That would be bad.
If she is chewing at it, though, it must be bothering her. Are you in an area with warm climate? It could be a bot fly. Rabbits can get these quite often. However, if it has frequently been below freezing in your area, this is probably not as likely.
http://www.medirabbit.com/EN/Skin_diseases/Parasitic/Cuterebra/Miyasis_botfly.htm
Since it is a bother to her, you probably want to have a vet look at it soon. She may need the area wrapped, or have her ability to reach at it restricted, at the very least to keep her from chewing. Even if it is a simple scab (which they usually will not chew at, and which doesn't look like that), it really should be looked at. Probably needs pain meds and professional wound dressing.
