For further technical details on their evolutionary history, you can explore the molecular study available on BMC Evolutionary Biology . Morphological discrimination of human lice (Anoplura - PMC
: They are typically dorso-ventrally flattened and have specialized tibio-tarsal claws to cling securely to host hair. anoplura
( Pediculus humanus humanus ): Associated with poor hygiene and often found in the seams of clothing. For further technical details on their evolutionary history,
( Pediculus humanus capitis ): Resides on the scalp and is common among school children. anoplura