Fam. 2. Schizonotidae (= Tartaridae).—This family contains only two genera, Schizonotus (= Nyctalops, Pickard-Cambridge, nom. preocc. Aves) and Trithyreus[[255]] (= Tripeltis, Thorell, nom. preocc. Reptilia). They are very small, pale-coloured forms (about 5 mm. in length), found in Burma and Ceylon.

Fam. 3. Tarantulidae, better known as Phrynidae. Pocock has shown that Fabricius established the genus Tarantula from the species T. reniformis in 1793, while there is no earlier record of Olivier’s Phrynus, established for the same species, than Lamarck’s citation of it in 1801. The family is divided into three sub-families, Tarantulinae, Phrynichinae, and Charontinae.

(i.) The Tarantulinae are new-world forms, represented by three genera, Tarantula, Acanthophrynus (Phrynopsis), and Admetus (Heterophrynus), in Central and South America and the West Indies.

(ii.) The Phrynichinae belong to the Old World, being found in Africa, India, and Ceylon. Phrynichus, Titanodamon and Nanodamon are genera of this sub-family.

(iii.) The Charontinae are natives of South-East Asia and the Pacific Islands. There are five genera and eight species.

CHAPTER XIII
ARACHNIDA EMBOLOBRANCHIATA (CONTINUED)—ARANEAE—EXTERNAL STRUCTURE—INTERNAL STRUCTURE.

Order III. Araneae.

(ARANEIDA,[[256]] ARANEINA.)

Arachnida breathing by tracheae and “lung-books.” Cephalothorax and pedicellate abdomen, the latter usually soft, and only very rarely showing any traces of segmentation. Two-jointed non-chelate chelicerae, the distal joint bearing the orifice of a poison-gland. The tarsal joint of the male pedipalp develops a sexual organ. The abdomen is furnished with spinning mammillae.

The true Spiders can readily be distinguished from allied Arachnid groups, with which they are often popularly confounded, by the presence of a narrow constriction or “waist” between the cephalothorax and abdomen, and of a group of “spinnerets” or external spinning organs beneath the hind portion of the body. Thus the so-called “Harvest-spider” or “Harvestman” is clearly not a Spider, for there is no constriction of its body into two parts, nor does it possess any spinnerets. It belongs to the Phalangidea. The same considerations will exclude the “Red Spider” of popular nomenclature, which must be referred to the Acarina or Mites.