In November 1961, the author accepted an offer of some specimens of Theraphosidae with the kind intentions of Dr. Kyuzabro Komoto, who is a Japanese medical doctor living in Hajai City of South Thailand. The spiders were all identified with Chilobrachys andersoni POCOCK, 1895, belonging to subfamily Selenocosminae, which are now found in that country. In this paper, the author has describecl scme of the form and habit of the spider, but the description of its habit is all based on the report of Dr. Komoto. One of the most interesting facts of the spider is the structure and its function of stridulating organ, which presents between the chelicera and the maxilla. The Chelicera is furnished with 6 long spines and about 50 short ones on the lower portion of the outer surface, the maxilla with about 50 vibratile baciliform bristles on the inner surface, and both are made to work on each other as a defiant attitude is assumed. The baciliform bristles of the maxilla are devided into 4 series of row, and, as a whole, the aspect resembles a lyre which is erected as 4 octarved. The author thinks that the long spikes of Chelicerae rub with the long bacilli of maxillae, and the short spines rub with the short bacilli of them, which make some kinds of sound. Therefore, at the notice of these function, the relation between spikes of chelicerae and the bacilli of maxillae is in parallel, not perpendicularly. Hereby, the author is heartily appreciated to Dr. Komoto for his sending the specimens.
Holotype (male): Yakushima Isl. 1-VIII-1961, Coll. T. Irie. Head narrower than thorax (38:72), longer than wide. Cervical grooves clear, but radial furrow indistinct. Median furrow depressed triangularly, Capapce flat, raised behind the head. Eye area occupying the entire breadth of head. Anterior eye row slightly procurved and posterior strongly procurved. MOA longer than broad, slightly narrower behind. Lateral eyes on tubercles, nearly contiguous. ALE smaller than PLE. AME larger than PME. PME equal to PLE. AME separated from each other by more than the diameter, from ALE by more than twice the diameter. PME also separated by more than the diameter, from ALE by more than three times the diameter. Both margins of fang furrow with three teeth each, between both margins with many scattered denticles. Maxillae square, with scopulae, as long as wide. Labium free, broader than long, of low triangle in shape. Sternum concaved in front, embracing the base of labium, with 5 radial keels of which posterior three high. Legs slender, with spines. The length of metatarsus plus tarsus longer than tibia plus patella. Leg formula 1234. Abdomen long, parallel sided, rounded in front, overlapping the hind part of thorax, slightly protruded beyond the spinnerets posteriorly. Epigastric plates with many transverse furrows. Epigynum as shown in fig. 1 (7).