Pediculus humanus,
internal anatomy of male seen from above.
a, anus; cns, ventral part of central nervous system; d, dilator; ht, heart; mg, midgut; mt, Malpighian tube; my, mycetome; r, rectum; sd and sg, salivary duct and glands; ts, testis.
(After Kahn and Nuttall.)