I have seen lice crawl. There was a girl in front of me in high school that had it crawling around all in her hair. I promise you that I noticed things started moving around in her hair and not just like a bug it was ALOT of little bitty things moving around in her hair. I felt really bad for her and didn't want to tell her, mostly because I didn't want to get that close, so I whispered it to the teacher. The poor girl was out for a week and came back with extremely short hair.
Yes they do crawl in the hair!!!!! that is how they spread so fast in children because when children are playing, reading books, doing blocks, etc they touch heads together. They move like lightning on a human hair shaft. Yes yes yes I said they crawl on hair. BUT if you picked one of those boogers off the head and laid it on a table, or a pillow or anything, It would lay there and wiggle its legs and not go anywhere. Their legs are designed only to shimmy up a hair shaft. I have done this. I picked one off my sons head to test the theory. Then I plucked a hair from my head, and layed it against the louse and it grabbed on quite fast and crawled up it. They do not move when not on hair. They NEVER jump. They only crawl when on a hair. They can move from one hair to another quite fast though.