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Show 1896.] SPIDERS FROM THE LOWER AMAZONS. 745 base of labicd plate ; 2nd almost obsolete ; 3rd marginal; 4th sub-marginal. Posterior pair of spinners a little longer than width of sternum. Carapace quite straight (in profile) behind eges. Patella and tibia iv. equal to length of carapace. Patella and tibia i. equal to length of carapace. Legs clothed with long hairs; feathery. Protarsus and tarsi i., ii., hi., and iv. broad, spatuliform. Habits arboreal; forming silken cgllnders under bark of trees or amongst foliage. Never having seen the type specimen of M. plumlpes, C. K,, one cannot speak with absolute confidence as to its generic characters. Specimens of T. sancti-vincentl, Walck., however, agree remarkably with the full figure of M. plumlpes and in the arrangement of the eyes which C. Koch has given, and there can be little doubt but that the two forms are congeneric. As distinct from Avicularia, they may be recognized by tbe anterior eyes forming an almost straight row, whereas in Avicularia they form a strongly pro-curved line. In Avicularia the fourth pair of legs is the longest; in Taplnauchenlus the first and fourth pairs are equall. Tibia and patella iv. are, in Avicularia, longer than the carapace; in Taplnauchenlus they are equal to it. The posterior pair of spinners in both these genera are longer than the width of the sternum. Otherwise in general characters the species of these two genera are very much alike; the anterior row of eyes, however, furnishing the best character-so far as one can judge from the material in hand. Mygale sancti-vincentl, Walck., 6*, Insectes Apteres, i. p. 216. -Walckenaer says: " L a quatrieme et la premiere paire de pattes 3ont presque egales " - " les yeux forment un carre long, transverse, dont la gibbosite est peu prononcee." The generic characters given above of Taplnauchenlus have been drawn from specimens of this species. Of. E. Simon, Proc. Zool. Soc. 1891, p. 553. St. Vincent. Species probably belonging to this genus hitherto described:- T. latipes, Auss. Verhandlungen zool.-bot. Gesel. 1876, p. 183. Venezuela. T. reduncus, Karsch, Zeit. ges. Naturwiss. p. 387, vol. liii. Costa Bica. Of Taplnauchenlus, M . Simon says :-" Les moeurs de ces 1 M. Simon in Proc. Zool. Soc. 1891, p. 583, gives the lengths of the first and fourth pairs of legs in T. sancti-vincenti (§) as i. 46'2 mm., iv. 48*5 m m . In this measurement the coxa is evidently not included ; if the coxa is included, the lengths of i. aud iv. are equal, namely, 59 m m . But of course there is no special value in the absolute lengths; nor must such characters be held as absolutely reliable. In an Avicularia, 8, n. sp. undescribed, for instance, and in A. rutilans, Auss., 8 > again, the first pair of legs is equal to, or, if anything, slightly longer than, the fourth, instead of vice versa. Whether thi3 character may ultimately prove to be more than of specific value or not, one would at any rate not regard it of sectional value as M . Simon does (Hist. Nat. A r-1. p. 133). Many of these characters, however, must only be looked upon as generally true of this or that group and subject to particular exceptions-convenient as guides to classification, but to be used with great caution. PROC. ZOOL. Soc-1896, No. XLVI1I. 48 |
