Life stages of the western blacklegged tick, Ixodes pacificus. From left to right: adult female, adult male, nymph, and larva.

Parasitic life stages of the western blacklegged tick (Ixodes pacificus). Left to right: adult female, adult male, nymph and larva. Millimeter ruler and pencil tip provide scale. Credit: California Department of Public Health
Credit: California Department of Public Health