MICRATHENA. 529 
Legs without spines, except that femora i, and ii. have three or four fine spines beneath, set on granules ; 
coxa 1. without a hook. 
Abdomen elongate, triangular when viewed in profile, the spinning-tube being conspicuous, finely granulose 
throughout, each granule bearing a fine hair; narrowed anteriorly, dilate behind the middle, having a 
prominence on each side in the posterior third, slightly dilate and finally narrowed, each posterior angle 
bearing a very short sharp cusp. 
The palpal bulb bears on the outer side a large falciform embolus, and the form of the tarsal hook is 
characteristic. 
Hab. Nortn America !~4789—_Mextco, Tepic (fide Banks !°), Chilpancingo, Rincon, 
Amula, Orizaba!? (H. HW. Smith); GuatemaLs, Guatemala city (Stoll), Magdalena 
near Antigua, Cahabon, Santa Ana, Motagua (Sarg); Costa Rica (Rogers).—SouTn 
AMERICA ®. 
Of this species Sarg remarks in his letters :—‘ Colour bright yellow, with overlaid 
reddish-orange, leaving only a few markings of the original paler yellow ; the indented 
spots are black ; below, the colour is more of a yellow-ochre.” 
Although the examples of this species (AZ. rugosa, Hentz) from the United States 
are very much smaller than those (Jf. matronalis, C. L. Koch) from Central and 
South America, I can find no real difference on which one could separate them. 
We must accept McCook’s identification of JZ. gracilis (Walck.) with IZ. rugosa 
(Hentz), and, judging from Abbot’s figures, there is no reason to doubt that his 
conclusion is correct. I have not, however, been able to compare well-authenticated 
males of these two forms. 
2. Micrathena mammillata. (Tab. L. figg. 4, 4 a-c, 2.) 
Acrosoma mammillatum, Butl. P. Z. 8. 18738, p. 427". 
Type, 2, in Mus. Brit. Total length, 9, 10 millim. 
In general characters this species is very similar to If. gracilis, the integuments of the abdomen being, as in 
the latter, closely and finely punctured throughout. The thoracic fovea is, however, not so deep, and the 
cusps on the abdomen are different in number and character, 
There are a pair of short anterior marginal cusps projecting outwards on each side of the base of the carapace ; 
these are followed along the sides by a group of three, and another of two, short, bluntly rounded cusps, 
the latter group situated about the middle. Dorsally there is a pair of anterior median, basally dilate, 
sharp spines directed straight forwards, followed on each side by a pair of closely adjacent, rather shorter 
cusps of the same character directed obliquely forwards, while posteriorly there is on each side a group of 
four cusps—the first quite small, a mere tubercle, the second, the longest, enlarged basally behind, the 
third, smaller, lying in the same plane, the fourth, still smaller, lying behind and below the third. 
Midway between the last pair of cusps and the spinners is a small circular convex boss formed by four 
muscle-scars, and immediately above the anal tubercle lies a blunt cusp, its apex directed downwards. 
The exact character of the abdominal cusps varies, however, in different examples. The vulva is very 
similar to that of MW. gracilis, consisting of a compressed scapus, excavate on each side, dilate basally, the 
two orifices being wide apart below the base of the scapus; they are much nearer to each other in 
the last-mentioned species, but the exact form of these parts varies much in individual examples. 
Hab. Mexico, 'Teapa (#1. H. Smith); Guatemata, Chamiquin, Cubilguitz, Cunen, 
Tikal, Menché, Rio Santa Isabel (Sarg) ; Panama, Bugaba (Champion).—Sovuru AMERICA, 
Santarem (I. O. P.-C.), Orinoco}. 
BIOL. CENTR.-AMER., Arachn. Aran., Vol. II., June 1904. 3 rf 
