I was recently given the opportunity to see some lice and I took advantage to put them on a Intel QX3 Computer Microscope. I took some movies and photos of one that was captured alive after one Nix treatment.
Live Louse 60x Magnification
This bugger was alive as you can see if you click on the mpeg link. (Note: the clip was 10 seconds long but the conversion to mpeg seems to speed that up about twice normal speed). The interesting parts for me were the claws for gripping hair and the internal organs that were pumping. I suspect that is the heart.
Egg sac or “Nit”
The egg sac or nits are more commonly found in an infestation. They are pouches attached to the hairs a few mm from the scalp.