170 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I25 



is dark rusty brown and the sternites are all light tan-pruinose. The 

 sidepiece of acafenangoensis appears almost square ; the clasper has 

 its outer margin well curved and its apex rather blunt, usually with 

 2 spines. S. virgatum has the sidepiece rectangular; the clasper is 

 rather straight along its outer margin and the apex is rounded with 

 usually I spine. The median prolongation of the adminiculum is 

 shorter and narrower, and the basal prolongations are broad and 

 spatulate in this species, while in virgatum the basal prolongations are 

 long, narrow, and pointed. S. virgatum is a larger species. The pupal 

 filaments are arranged in 2 groups of 2 filaments and 4 single ones, 

 while in virgatum they are arranged in 2 groups of 3 filaments, and 

 with only 2 single ones. 



S. acafenangoensis can most easily be distinguished from rubicundu- 

 lum by the following characteristics of the latter species : The apical 

 margin of the adminiculum is straight with a very long, slender median 

 prolongation emerging perpendicular to it. The clasper is not as 

 curved on its outer margin as that of acafenangoensis and it bears only 

 I apical spine. The mesonotum of the female is evenly clothed with 

 golden-yellow scalelike hairs. The outer basal angle of the expansion 

 of the genital fork is almost 90°. The pupal filaments are arranged 

 like those of virgatum. 



S. acafenangoensis appears closest to ^. mafhesoni, but the following 

 points of difference will establish their individuality: The abdomen 

 of the female mafhesoni is dark brown with the posterior margins of 

 segments 2 through 7 being gray-pruinose. The sternites of the ab- 

 domen of the male mafhesoni are evenly pruinose rather than being 

 shiny light brown with a median, longitudinal, black band, as in 

 acatenangoensis. The hind femur of the male mathesoni is yellow, 

 with subbasal and apical dark-brown rings, and the basitarsus is al- 

 most completely yellow ; in acatenangoensis the femur lacks the sub- 

 basal dark ring, and the basitarsus is yellow only on its basal half. 

 The pedisulcus of the same leg is much deeper in acafenangoensis. 

 The adminiculum of acafenangoensis has the median prolongation 

 narrower, the lateral margins of the latter being parallel rather than 

 converging toward the apex. The body of the adminiculum of acate- 

 nangoensis is narrower and the basal prolongations are longer. The 

 latter structures are broad and hyaline, each ending in a spatulate 

 plate with fingerlike extensions; in mathesoni these are narrower, 

 more heavily sclerotized, each ending in a rather sharp point. The 

 arms of the adminiculum of acatenangoensis have the teeth at the 

 apex concentrated to form a dome-shaped structure, while in mathesoni 

 the teeth are more dispersed. The clasper of the former species has 2 



