SUPER-ORDER PHALANGIOMORPHAE. Distinguished from the pre ceding groups of Epectinates in the following characters :—(r ) The cephalothorax and abdomen are widely confluent. (2) The sternum of the genital somite is indistinctly defined in the adult, the genital orifice being thrust forward between the last pair of domen sometimes showing indications of ten segments defined by shallow grooves, typically without trace of segmentation.
Sub-order Euacari. Parasitic or free-living, sometimes aquatic or marine, forms with a short abdomen and four pairs of normal locomotor legs. Families Oribatidae, Gamasidae, Ixodidae, Trom bidiidae, etc., classified by the spiracles.
Sub-order Tetrapoda. Vegetable parasites with the abdomen very long and annulated, the third and fourth pairs of legs absent. Family Eriophyidae (Gall-mites) .
Sub-order Vermiformia. Parasitic forms living in the hair follicles of Mammalia, with the abdomen long and annulated and legs. (3) There is a pair of foetid glands opening upon the cephalothorax. (4) The basal segments of the first and generally of the second pair of legs act as jaws.
Order Opiliones. Mandibles chelate and three jointed. Palpi variable, their basal segments acting as jaws. Legs locomotor in function. Abdomen containing ten somites more or less fused to gether, the second with a pair of spiracles. Male and female re spectively with a long penis and ovipositor.
Sub-order Palpatores. Palpi small, pediform. Sternum of cephal othorax short.
Tribe Eupnoi. With accessory spiracles on the fifth segment of. the legs. Family Phalangiidae (Phalangidum).
Tribe Dyspnoi. No accessory spiracles on the legs. Families Nemastomidae, Trogulidae, etc.
Sub-order Laniatores. Palpi prehensile with a piercing claw. Sternum of cephalothorax long and usually very narrow. Families Gonyleptidae (Gonyleptis), Oncopodidae (Oncopus), etc.
Sub-order Cyphophthalmi. Palpi pedif orm ; sternum of cephalo thorax minute or absent, the foetid glands are glands on a high tubercle. Family Sironidae (Siro, Stylocellus) .
The Opiliones are found in temperate and tropical latitudes of the eastern and western hemispheres. Most of the British species, belonging to the Phalangiidae, are remarkable for the extreme length and thinness of their legs and the small pill-like bodies.