[The female when fully replete is 11 mm. long, when fasting 3·86 mm.; the shield is heart-shaped and punctate, body finely hairy; palpi short and broad; labium shorter, and tarsi of all the legs more truncate than in I. ricinus. The colour of the distended body is drab and somewhat waxy; rostrum, shield and legs light testaceous. The male varies from 3·5 to 4·0 mm. long, and is reddish-brown in colour with lighter legs; the shield is punctate and leaves a narrow margin around the body; the body is elliptical, almost as large in front as behind. There is a spine on the coxæ of the first pair of legs, which is shorter than in the male I. ricinus and longer than in the female. The genital orifice is opposite the interval between the second and third pair of legs. The fasting nymph is 1·76 mm. long, light bluish-grey, margined and transparent, with four large posterior intestinal marks joined together behind the shield and smaller ones extending to the front and sides. When fully distended it is uniformly brownish-white; shield, legs and rostrum pale testaceous. The larva varies from 0·88 mm. when fasting to 1·76 mm. when gorged. Its body is light, but gradually becomes darker, with similar intestinal marks to ricinus.
[This tick is very common, especially on ferrets, stoats and hedgehogs. It is also found on sheep, cattle, etc. The males do not generally occur in company with the females on the host. Pairing probably takes place on the ground.—F. V. T.]
Genus. Amblyomma, Koch.
Amblyomma cayennense, Koch, 1844.
Syn.: Amblyomma mixtum, Koch, 1844; Ixodes herreræ, Dugés, 1887; Amblyomma sculptum, Berlese, 1888.
Characterized by the possession of eyes. The male measures 3·8 mm. in length by 3 mm. in breadth; the female 4 mm. in length by 3 mm. in breadth, but when full of blood may become 13 mm. in length and 11 mm. in breadth. They are common in the whole of Central America (Carrapatas), and attack mammals, amphibious animals and man.[340]
[This species was described by Fabricius. It occurs in Cayenne, Guiana, in Southern Texas, Florida, California, Mexico, Guatemala, Honduras, Nicaragua, Costa Rica, Panama, Bermuda, Cuba, Jamaica, Trinidad, Colombia, Venezuela, French Guiana, Brazil, Paraguay and the Argentine. It is called the silver tick. It frequently attacks man. Schwarz and Bishopp (Bull. 105, U.S. Dept. Agric., p. 158) heard of one man whose legs were well covered with suppurating sores and who was ill from the attack of these ticks and the wounds produced by scratching, and records other cases of their swarming on man. Newstead (Ann. Trop. Med. and Par., 1909, iii, No. 4, p. 442) records it as the worst pest to man in Jamaica.—F. V. T.J
Amblyomma americana, Linnæus.
The so-called long star tick, from the silvery spot on the apex of the scutum of the female. It will attack any mammal and even birds and also man. It occurs in North America, and also in Brazil, Guiana and Guatemala. Its punctures frequently end in suppuration. In the Eastern and Southern States man is more frequently attacked by this species than any other. Moss-gatherers in Louisiana are badly attacked by it.[341] It also attacks the milkers in dairies. Attempts to transmit Texas fever failed with this species.
Amblyomma maculatum, Koch.