One of the seven orders into which he divided them was " Aptera ", meaning wingless, a group in which as well as fleas, he included spiders, Anoplura ( sucking lice ) and Siphonaptera ( fleas ), at the same time separating off the arachnids and crustaceans into their own subphyla.
12.
At least three species or subspecies of Anoplura are parasites of humans; the human condition of being infested with sucking lice is called pediculosis . " Pediculus humanus " is divided into two subspecies, " Pediculus humanus humanus ", or the body louse, sometimes nicknamed " the seam squirrel " for its habit of laying of eggs in the seams of clothing, and " Pediculus humanus capitis ", or the head louse . " Pthirus pubis " ( the crab louse ) is the cause of the condition known as crabs.
