Under a relatively low magnification of 97x, this 2006 scanning electron micrograph (SEM) depicted a dorsal view of a male body louse, Pediculus humanus var. corporis. Occupying the field of view, was the insect's left leg of its first pair of legs. There was a piece of debris attached to the distal claw tip of this appendage. The 'jointed' nature of its extremities, designates this organism as a member of the phylum Arthropoda, and the fact that there are three pairs of legs, the louse is, thereby, placed into the class, Insecta. Note the small, 'hair-like' structures adorning the exoskeletal surface of this insect. These are known as 'setae', and are not hairs at all, but extensions of the chitinous exoskeletal surface, which provide the organism with sensorial data about its surroundings.
CDC/ Joseph Strycharz, Ph.D.; Kyong Sup Yoon, Ph.D.; Frank Collins, Ph.D.
November 2, 2012