Description of life history stages of poultry shaft louse, Menopon gallinae (Phthiraptera: Amblycera, Menoponidae)

Nymphs of successive generations of Menopon gallinaeI (L. 1758), parasite on Gallus gallus f. domestica, highly resemble to each other from the moment of emergence and show the number of abdominal segments characteristic of adult form. Apart from evident differences in body size, the relative size of abdomen (head, thorax and abdomen ratio), rising chitinization of the cuticle, the succesive nymph stages can also be distinguished on the basis of progression of chaetotaxy. Furthermore, brush (spiniform setae) on fourth sterna and spiracular aperture become evident in third instar nymphs.