158 PROCEEDINGS OF THE NATIONAL MUSEUM vol.75 



On the type and on some of the paratypes the fascia on the first 

 tergite incloses a pair of small, approximated, black, discal spots. 

 On some specimens these spots are joined, forming a single median 

 spot. Variation in the character and extent of the maculations is 

 usually great in species of this genus, but in the case of this species, 

 as represented by the 14 specimens at hand, variation in the macu- 

 lation is very slight. All males have a black border at the base of 

 the clypeus; this black border is lacking on all females. On the 

 females the discal marks on the scutum are broad and on some these 

 marks assume a broken U-shaped form. 



Length 14 mm. Described from seven males and seven females 

 (including the type and allotype), of which 13 bear the label, "La 

 Rioja, W. Argentina, B. P. Clark, donor." The remaining speci- 

 men, a female, bears the label, " Pie de Palo, San Juan, Argentina, 

 11 March, 1920, Cornell U. Expedition." 



Tyye and cdloMjpe.—Q^it. No. 40851, U.S.N.M. 



MICROBEMBEX SULPHUREA (Spincla) 



Figures 49, 50 



Bemibex sulphtirea Spinola, Gay's Hist. Fis. y Polit. de Chile, vol. 6, 1853, 



p. 319. 

 Bemhex sulfurea Handlirsch, Stiz. Akad. Wissensch. Wien, Math. Nat. CI., 



vol. 102, 1893, p. 885.— Dalla Torre, Cat. Hym., vol. 8, 1897, p. 514. 



The males of this species have the hind femora dilated at the 

 middle point (fig. 49), a character that, so far as I am aware, is 

 not possessed by any other species of the genus. Furthermore, the 

 spine of the eighth sternite has a distinct hook at the tip, as is shown 

 in Figure 50. Apparently Handlirsch overlooked this in his de- 

 scription of the species. The females (and males also) have the 

 clypeus strongly prominent so that its junction with the frons at 

 the midline forms an angle more nearly approaching a right angle 

 than on any other species except nasuta. The apical emargination 

 of the clypeus for the junction with the labrum is greater than a 

 semicircle, so that the depth of the emargination compared with 

 its extreme width is approximately as 3 is to 4. The size of the 

 individuals, the color of the maculations, and the extent of their 

 development all vary greatly. 



Among the specimens of this species before me are two males, iden- 

 tified by Handlirsch and bearing the label, " Oberer Magdalenen, 

 Strom " ; a male identified by Kolil and bearing the label, " Chile, 

 Concepcion, 1903, Herbst " ; a female identified by Handlirsch and 

 bearing the label, " Brasilien " ; and a female identified by Reed and 

 bearing the label, " Chile, E. C. Reed." In addition to these I have 



