OPAS. 185 
base furnished on the outer side with a series of two parallel longitudinal rows of long bent hairs, their 
extremities taking a circular form ; each hair springs from a minute tubercle. 
Falces powerful, moderately long, strongly and roundly prominent at their base in front. 
Maxille moderate in length, broad, truncate at their extremity, which is rounded on the inner side, strongly 
divergent. 
Labium short, much broader than high, rounded at the apex. 
Sternum broadly heart-shaped and convex, its hinder extremity rather broadly drawn out between the coxee of 
the fourth pair of legs. 
Abdomen subcylindric, its posterior extremity produced into a caudiform prominence. 
Opas lugens, sp. n. 
Adult female, length to the spinners 13 lines, to the extremity of the abdominal prominence 22 lines. 
Cephalothorax, falces, mawille, labium, and sternum dark brown ; legs and palpi paler, excepting the femora of 
the former. 
Eyes of the hind-central pair separated from each other by less than a diameter’s interval, and by double that 
interval from the hind-laterals. 
The abdomen has its fore extremity rather broadly and obtusely produced in front. Its upperside is dull 
yellow-brown, with a blackish tapering band down the middle, and alternate black and silver oblique 
stripes of different length and strength on each side; the posterior prominence is black, rounded and a 
little the largest at its extremity, at its base on each side is a silvery dash or stripe. There is also a 
silvery spot in the middle of the fore extremity, and along the lower part of each side is a somewhat 
wavy, slender, broken, pale yellow-brown line marked with silvery spots. The underside of the abdomen 
is black, marked with six silvery spots, the four posterior ones forming a quadrangle broader than long 
close in front of the spinners; the anterior pair of spots are elongate and near the genital aperture, which 
is of a simple, somewhat tranverse, oval form. Spinners short, compact. 
Hab. Mexico, Teapa in Tabasco (H. H. Smith). 
This species bears a close general resemblance in form and markings to Argyroepeira 
(Emert.), but differs in the position of the eyes, the length of the legs, the absence of 
spines on them, and the very peculiar series of hairs on small tubercles on the femora 
of the fourth pair. 
Opas merens, sp. n. 
Adult female, length 23 lines. 
This spider is nearly allied to O. lugens, but may be at once distinguished from it by the far less developed 
prominence of the hinder extremity of the abdomen. In the present species this is very obtuse and 
extends but little beyond the spinners. The colour of the cephalothorax varies from pale brownish-yellow 
to darkish yellow-brown ; the legs are yellow to yellow-brown, annulated, chiefly at the extremities of the 
femora, genus, and tibie, with dark brown to black ; a less distinct annulus towards the base of the tibie. 
The abdomen is very much and roundly produced forwards, the connecting pedicle being placed exactly 
halfway between its fore extremity and the spinners. Its colour is dull black, the fore extremity has on 
each side a strong well-marked silvery crescent, and there are other silvery spots and markings, both on 
the sides and on the upperside, differing in pattern from those of O. lugens ; the underside has six small 
silvery spots as in that species. The posterior pair of legs are furnished on the outer side of the femora 
with a similar series of minute tubercles and long slender curved hairs. The genital aperture is, though 
somewhat like that of O. lugens, yet characteristically different, being transverse-oval, with a prominent 
point in its anterior margin. 
Hab. Mexico, Teapa in Tabasco (H. H. Smith). 
Mr. Smith speaks of the snares of this spider as regularly geometric, from 8 to 10 
inches in diameter, and made in damp shady places on herbs or low branches. The 
BIOL. CENTR.-AMER., Arachn. Aran., June 1896. 2 Bf 
