1896.] SPIDERS FROM THE LOWER AMAZONS, 745 
base of labial 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 eyes. 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., ii., and iv. broad, spatuliform. Habits 
arboreal; forming silken cylinders under bark of trees or amongst 
foliage. 
Never having seen the type specimen of M. plumipes, C. K., one 
cannot speak with absolute confidence as to its generic characters. 
Specimens of 7’. sancti-vincenti, Walck., however, agree remarkably 
with the full figure of J. plunvipes 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 the 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 Tapinauchenius the first and fourth pairs are equal'. Tibia and 
patella iv. are, in Avicularia, longer than the carapace; in Tapin- 
auchenius 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-vincenti, Walck., 3, Insectes Aptéres, i. p. 216. 
—Walckenaer says: “‘ La quatri¢me et la premiére paire de pattes 
sont presque égales ”—“ les yeux forment un carré long, transverse, 
dont la gibbosité est peu prononcée.” The generic characters given 
above of Tapinauchenius have been drawn from specimens of this 
species. 
Cf. E. Simon, Proc. Zool. Soc. 1891, p. 553. St. Vincent. 
Species probably belonging to this genus hitherto described :— 
I’. latipes, Auss. Verhandlungen zool.-bot. Gesel. 1876, p. 183. 
Venezuela. 
T. reduncus, Karsch, Zeit. ges. Naturwiss. p. 387, vol. liii. 
Costa Rica. 
Of Tapinauchenius, M. Simon says :—‘“ Les meurs de ces 
1 M. Simon in Proce. Zool. Soc. 1891, p. 583, gives the lengths of the first 
and fourth pairs of legs in T. sancti-vincenti (Q ) as i. 46°2 mm., iv. 48:5 mm. 
In this measurement the coxa is evidently not included ; if the coxa is included, 
the lengths of i. and iv. are equal, namely, 59 mm. But of course there is no 
special value in the absolute lengths; nor must such characters be held as 
absolutely reliable. In an Avicularia, g, n. sp- undescribed, for instance, and 
in A. rutilans, Auss., $, again, the first pair of legs is equal to, or, if any- 
thing, slightly longer than, the fourth, instead of vice versd. Whether this 
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. 
Ar. i. 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. Zoor. Soc.—1896, No. XLVIII. 48 
