The nymphs I, II, III, and adult male and adult female stages of Mulcticola macrocephalus (Kellogg) (Phthiraptera, Ischnocera: Philopteridae), a monoxenous species of chewing louse infesting common nighthawk, Chordeiles minor (Forster) (Caprimulgiformes: Caprimulgidae), in North America, are described. Line drawings of whole nymphs and adults are presented, as are details of anterior dorsal head plates, metasternal plates, female subvulvar plates, and male genitalia. Ontogenetic characters exhibited during the postembryonic development of this species of chewing louse are described and discussed in relation to previous information in the literature.

若虫I，II，III以及成年阶段的Mulcticola macrocephalus（Kellogg）（Phthiraptera，Ischnocera：Philopteridae），是一种咀嚼虱子的单一异种，感染了普通夜鹰，Chordeiles minor（Forster）（Caprimulgiformes：Caprimulgidae），在北美有描述。提出了整只若虫和成虫的线条图，以及前背头板，后胸骨板，女性外阴板和男性生殖器的细节。与文献中的先前信息相关地描述和讨论了这种咀嚼虱的胚后发育过程中表现出的个体遗传特征。