Amyotrophic lateral sclerosis
Aug. 04, 2021
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Comparison of a male (left) and a female (right) American dog tick, Dermacentor variabilis (dorsal views). Note the smaller size of the female’s scutum compared to the male’s larger scutum. From the Latin word for “shield,” the scutum, ie, dorsal shield, covers only a small part of the female’s dorsal surface, thereby enabling her abdomen to expand and become engorged during feeding. The male’s scutum covers his entire dorsal surface and is mottled with brown markings overall, whereas the female’s small scutum sports a cream-colored gray surface. Photographs (1975). (Courtesy of the Public Health Image Library, Centers for Disease Control and Prevention. Public domain.)