After exposure to the host as unfed larvae, most Dermacentor albipictus (Packard) larvae engorge and ecdyse to nymphs in 9–10 days. Nymphs engorge and ecdyse to adults 15–20 days after infestation, with most males ecdysing before females. When nymphs start to feed, spermatogenesis begins with increased mitotic activity and testicular growth. In adult ticks fed 3 days, testes contain spermatogonia, early spermatocytes, growth-stage spermatocytes, meiotic figures, early spermatids, and partially and fully elongated spermatids. The latter are also present in the vasa deferentia. Spermatogenesis in D. albipictus resembles that found in other 1-host ticks.