Are pubic lice a red colour?

Yes: Here is an image of a pubic louse and a head louse. Hope this helps!

PUBIC LICE: Lice may be tan to brown gray & the size of a sesame seed. Nits are tiny, light to white colored deposits that adhere to hair. Pubic lice may be found on genitalia, underarms, chest or even eye brows. Skin may have small pink or reddish bump with a central dot. The skin surrounding older bites may be purple or blue.