Genus. Dermacentor, Koch.
Dermacentor reticulatus, Fabricius, 1794.
Syn.: Acarus reticulatus, Fabr., 1794; Ixodes reticulatus, Latreille, 1806; I. marmoratus, Risso, 1826.
This tick is provided with eyes, but it is distinguished from Ixodes and analogous genera by the lack of the abdominal plastron in the male, which measures 5 to 6 mm. in length by 3·5 mm. in breadth. The female may attain 16 mm. in length and 10 mm. in breadth. It is found in the South of Europe, in Asia, and in America; it attacks chiefly oxen, sheep and goats, and occasionally man.[343]
[This tick sometimes causes much annoyance to human beings. It was once most troublesome at Revelstoke. Specimens have recently been found on fowls, turkeys and pheasants in Kent.
[Other synonyms are as follows: Cynorhæstes pictus, Hermann, 1804; Crotonus variegatus, Dumeril, 1829; I. pictus, Gervais, 1844; Dermacentor albicollis, Koch, 1844–1847; D. pardalinus, Koch, 1844–1847; D. ferrugineus, Koch, 1844–1847; Ixodes holsatus, Kolenati, 1857; Pseudixodes-holsatus, Haller, 1882; Hæmaphysalis marmorata, Berlese, 1887.
[The female when fasting is 3·86 mm. long by 2 mm. wide. The body is depressed, larger behind and reddish-brown in colour. The shield is very large and extends to the level of the third pair of legs, with a few large and many small punctations, milky white, variegated with reddish-brown. Sexual orifice opposite the coxæ of the second pair of legs. Coxæ of the front legs are deeply bifid, the others with a moderate spine. When gorged light brown, and may reach 16 mm. When depositing eggs the female is mottled with dark brown above and below. The male is like the female. The shield is reddish-brown, variegated with a milky white pattern. Coxæ of the fourth pair of legs three times the size of the third. There is a sharp backwardly pointing spine on the second palpal segment, also seen (but smaller) in the female. Length 4·20 mm.
[According to Mr. Wheler this is a very variable species both in size and colour. It occurs in England on sheep, but not commonly. It has probably been introduced into Britain. Besides the animals mentioned above it is also found on deer.—F. V. T.]
Dermacentor venustus, Banks.