540 ARANEIDEA. 
31. Micrathena sedes. 
Acrosoma sedes, Getaz, An. Inst. Costa Rica, iv. p. 105 ( 2)’. 
Hab. Costa Rica, Palmares (Pitéier 1). 
TRICANTHA. 
Acrosoma, sous-genre Tricantha, E. Simon, Hist. Nat. Araign. i. p. 293 (1864). 
Type 7’. tricornts, K. Simon. Brazil. 
It is probable that the type of Tricantha is identical with Plectana tricuspidata, 
Blackwall [Ann. & Mag. Nat. Hist. (3) ii. p. 838 (1863)], from Rio Janeiro, but one 
cannot be sure without actual comparison. 
1. Tricantha tricornis. (Tab. LI. figg. 26, 26a, 2.) 
Tricantha tricornis, E. Simon, Hist. Nat. Araign. 1. p. 293, fig. 186 (?)'°. 
Type, 2, in coll, E. Simon. Total length, including posterior spine, 6 millim. 
Carapace broader than long, wider behind, cordiform. Cephalic region tuberculiform, convex, raised, produced 
anteriorly, overhanging the clypeus. Eye-groups closely situate, posterior row almost straight, anterior 
row slightly procurved, central quadrangle broader than long, narrower in front. Posterior centrals 
nearly two diameters apart, one diameter from anterior centrals, the latter being themselves one diameter 
apart ; lateral eyes almost in contact, posterior laterals one and a half diameters from the posterior centrals. 
Clypeus as high as three diameters of an anterior central eye. Sternum longer than broad, triangular, 
produced between coxee iv., coalescing with the dorsal chitin of the carapace. Legs 4, 1, 2, 3, devoid of 
spines, patelle strongly geniculate. 
Abdomen triangular, broader in front, having a long stout spine at each anterior angle and a similar spine at 
the central posterior angle, the apices of the three spines forming an equilateral triangle. The direction 
of the spines varies with the condition of the spider and the shrinkage or otherwise of the abdomen; the two 
anterior ones, in normal cases, are directed forwards and slightly upwards, the posterior spine backwards 
and more decidedly upwards. The whole abdomen is covered with a horny integument, the dorsal area 
having a median series of five pairs of sigilla and a lateral row of four sigilla on each side. The spinners 
are enclosed at the apex of a tubular sheath as in Gusteracantha and Micrathena, the spiracular orifice 
being as in these genera also situated on the anterior margin of the tube. 
For vulva, see Plate. 
Hab. GuatTeMALa, Montafia de Chilasco (Sarg !).—Braziu 1. 
The systematic position of the following genera and species of the family Argyopida 
is doubtful :— 
HYPOGNATHA. 
Hypognatha, Guérin, Rev. Zool. (1839) p. 110; E. Simon, Hist. Nat. Araign. édit. 2, i. p. 874. 
Calydna, O. P.-Cambridge, Ann. & Mag. Nat. Hist. (4) xiv. p. 174 (1874). 
Mutina, O. P.-Cambridge, P. Z.8. 1881, p. 771. 
1. Hypognatha nasuta. (Tab. LI. figg. 27, 27.4, ¢; 28, 28a, 2.) 
Hypognatha nasuta, O. P.-Cambr. Biol. Centr.-Amer., Arachn. Aran. i. p. 222 (9 2)". 
Type d, gynetype @, in coll. Godman & Salvin. Total length, ¢ 2-25, 2 3 millim. 
Hab. Mexico, Teapa in Tabasco (H. H. Smith 1). 
