A reader in Arizona wrote to us about a black and gray larva that crawled into her bed and bit her on the hand. Naturally, this concerned her, and she is trying to figure out what she found. The larva, which is about a half an inch (one centimeter) in length, was a bit menacing in that even after the reader removed it from her hand, it started crawling back toward her, and it was only when she shined light on that it backed away. What type of black and gray larvae might crawl into your bed and bite you?