Original: Lice ( singular : louse ) , ( order Phthiraptera ) , also known as fly babies or Nits , are an order of over 3,000 species of wingless insects ; three of which are classified as human disease agents .
Simplified: Lice ( singular : louse ) , ( order Phthiraptera ) are an order of wingless insects . There are more than 3,000 different species ; three are classified as human disease agents .