Ixodes ricinus
Ixodes ricinus, the castor bean tick, is a chiefly European species of hard-bodied tick. It may reach a length of 11 mm (0.43 in) when engorged with a blood meal, and can transmit both bacterial and viral pathogens such as the causative agents of Lyme disease and tick-borne encephalitis.
Description
In common with other species of Ixodes, I. ricinus has no eyes and is not ornate; it has no festoons (wrinkles along the posterior margin). The palpi are longer than they are wide, and there is an anal groove above the anus. It has a hard dorsal shield which covers the entire opisthosoma (abdomen), but only part of it in females and nymphs.I. ricinus is the largest of the three common species of Ixodes in the British Isles (the other two being I. canisuga, the "British dog tick", and I. trianguliceps, the "vole tick"). Adult males are 2.4–2.8 millimetres (0.09–0.11 in) long, and unfed nymphs are 1.3–1.5 mm (0.05–0.06 in) long; females are 3.0–3.6 mm (0.12–0.14 in) long before feeding and 11 millimetres (0.43 in) long when engorged.