OCR Text |
Show 1901.] ON NEW TRAP-DOOR SPIDERS. 207 4. On some new Trap-door Spiders from China. By R. I. POCOCK, F.Z.S. [Received February 11, 1901.] (Plate XXI.1) The most interesting species described in this paper are the discovered by Mr. J. La Touche and Mr. C. B. Pickett at Kuatun in North-west Eokien. One of these, Halonoproctus ricketti, is the representative of a new genus belonging to a specialized group of Ctenizidae, hitherto known only from the Sonoran area of North America ; the other, Latouchia fossoria,' is a more typical Ctenizoid apparently belonging to the same genus as the spider that Simon erroneously identified as Acattyma roretzi of L. Koch. The genus Latouchia is related to the Mediterranean genus Cyrtocarenum. The third genus, Nemesia, has hitherto been regarded as confined to the Mediterranean Eegion. The record of Macrothele from the Chinese area fills a gap in our knowledge of the distribution of the genus, the representatives of which were previously known from the Mediterranean Eegion, from Burma, Java, and New Zealand. Hence, assuming that it had a northern origin, it is admissible to suppose that Macrothele made its way into the Oriental Eegion and New Zealand by way of China. Further collecting will, in all probability, show that both this genus and Nemesia have a continuous distribution across Central Asia from China to the Mediterranean area. Subfamily HALONOPROCTINJE, nov. In Mexico and the Southern States of North America there are two peculiar genera of Spiders, referred to the family Ctenizidae, and characterized by the remarkable modification in the shape and other structural points of the abdomen. In the typical Ctenizidae, as in most other Trap-door Spiders, the abdomen is tolerably evenly oval, with the integument soft, smooth, and covered with silky grey pubescence, the sigilla, or muscular impressions, on the dorsal side being small and relatively inconspicuous. But in the genera above mentioned, namely Cychcosmia and Chorizops, the integument is of a leathery consistency, and is folded into a number of narrow ridges separated by corresponding grooves, which, except in the ventral area behind the epigastric fold where they are transverse, run in a longitudinal directiona. 1 For the explanation of the Plate, see p. 215. 2 A possible exception to this character is met with in Cychcosmia theveneti of Simon, which is said to have the integumeut ungrooved. The abdomen of the only known example, however, is described as " valde detritum." Hence the absence of folds is perhaps attributable to badness of preservation. It is possible, too, that the integument is sufficiently elastic to admit of considerable stretching, in which case the folds might disappear under the influence of distension of the abdomen. |