8o 
Psyche 
[March 
both sexes but the ventral scutum varies considerably in shape and, to 
some extent, also in size (Figs. 5, 10). In females the ventral 
scutum bears a more or less distinctive but obscure epigynal area show- 
ing an irregularly twisted minute canal. In the male the division 
between epigastric and ventral scuta is not clear but there is a genital 
aperture showing quite clearly. The six spinnerets are moderately 
well developed with no special modifications. 
Key to the known males of Ischnothyreus from 
Central America and the West Indies 
1 a. Species with a conspicuous knob at base of fang (Fig. 2) 
I. peltifer, p. 
ib. Species without such a knob at base of fang as given above 
(browni, indressus) 2 
2a. Species with a relatively long, curved, somewhat lobulate ex- 
tension of the palpal tarsal bulb (Fig. 12) I. browni, p. 
2b. Species without such an extension of the palpal tarsal bulb as 
given above I. indressus, p. 
Ischnothyreus peltifer (Simon) 
Figures 1-10 
Ischnaspis peltifer Simon, 1891: 562. The female holotype from St. Vincent, 
B. W. I. is in the British Museum (Natural History), examined. 
Ischnothyreus peltifer, — Simon, 1893: 298; (not male p. 299, fig. 264). 
Petrunkevitch, 1911: 127; 1928: 88; 1929: 66; Bryant, 1940: 266; 
Roewer, 1942: 287; Chickering, 1951: 219; Bonnet, 1957: 2309. 
Dysderina antillana, — Bryant, 1942: 324; 1948: 340. 
In view of the confusion in the literature regarding this species I 
have thought it desirable to select a male and a female for description 
from St. Vincent, B. W. I., the type locality. 
Male. Total length 1.67 mm, including extended spinnerets. 
Carapace .75 mm long; .57 mm wide opposite interval between sec- 
ond and third coxae where it is widest ; about .3 1 mm tall ; regularly 
arched from PE to beginning of posterior declivity which is quite 
steep along upper two thirds and then much less so to posterior 
border; surface quite smooth and shiny. Eyes: six in two rows, 
quite compactly arranged (Fig. 1); AME lacking; posterior row 
occupies about 5/7 of width of carapace at that level and is very 
slightly procurved, viewed from above. Ratio of eyes ALE : PME : 
PLE = 7 : 7.5 : 6.5. All eyes somewhat oval in outline (long 
diameters always used in measurements). ALE separated only by a 
line; separated from PME by about 2/7 of their diameter and from 
PLE only by a narrow line. All posterior eyes contiguous. Height 
of clypeus nearly equal to diameter of ALE. Maxillae: convergent; 
