Abstract The hard tick Dermacentor parumapertus is an ectoparasite commonly found on hares and rabbits and occurs over much of the western United States. These ticks are rarely encountered except by hunters or scientists collecting rabbits for study. Herein we describe 74 adult D. parumapertus ticks (21F, 53M) removed from 8 black-tailed jackrabbits, Lepus californicus, in central Utah, and 13 adult D. parumapertus (7F, 6M) found on 4 L. californicus in western Texas. The Utah ticks were barely ornamented. Females displayed only slight gray ornamentation near the posterior edge of the scutum and whitish-gray spots distally on the femur of legs II, III, and IV; males were completely devoid of any ornamentation. In contrast, Texas specimens were richly ornamented in white, closely resembling D. variabilis. Females were brightly marked with white (not gray) on the scutum and had white spots distally on all femurs. Males from Texas were variously ornamented along the posterolateral margins of the scutum and displayed white spots distally on all femurs. Documentation of this variability in ornamentation in D. parumapertus is important, particularly as white-marked specimens can easily be confused with D. variabilis and since both species have been reported from rabbit hosts
