

I to the abdominal region, Tarsi one- < ented Abd 



usually >h<M-t ;m<l broad, ci^lit- to ten segmented. Cerci al 







FIG. 19. Ptcronarcys regalis. A, nymph (after NEWPORT); B, imago. Slightly reduced. 



FIG. 20. Hexagenia variabilis. A t nymph; B, imago. Natural size. 



Biting lice, or bird lice, parasitic on birds and a few mammals, feeding 

 on feathers, hair or skin. Example, Menopon (Fig. 18). More than 

 fifteen hundred species have been described. 



