At a low magnification of 95x, this 2006 scanning electron micrograph (SEM) depicted an enlarged dorsal view of the cephalic, or head region of a male louse, Pediculus humanus var. corporis. In this particular view, the louse's 'haustellum' is withdrawn, or internalized inside the mouth region of the insect's cephalic region. The haustellum is a tube-like structure, fromed from what is believed to be a modification of the labium, but is armed with teeth, which act to grab, and hold on to the skin surface of its host while obtaining its blood meal. The insect pierces the host's skin with its sharply-pointed set of three stylets, which together for what is termed the fascicle. The pair of jointed bilateral antennae and the insect's body sport sensorial 'hairs' known as "setae', both of which provided the organism with a "picture' of its environment, by taking readings in thermal, chemical, and mechanical changes encountered in its immediate surroundings.
CDC/ Joseph Strycharz, Ph.D.; Kyong Sup Yoon, Ph.D.; Frank Collins, Ph.D.
November 2, 2012