82 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



in the following species this character is in great part produced by 

 the apical borders of the segments on the posterior surface. The 

 ultimate segment is curved, flattened dorso-ventrally, pointed at the 

 apex, and in length somewhat less than the combmed length of the 

 two segments immediately preceding. The middle femora below 

 are beset with numerous short spinelike teeth and the middle tibiae, 

 slightly carinate on the inner surface, have the apical margin on the 

 anterior side drawn out into a process bearing a short spine at its tip. 

 The middle metatarsi are curved on the inner side and bear near the 

 base four spines. The second and sixth stemites are devoid of pro- 

 cesses, the seventh bears a pair of carinae that diverge basally, and 

 the eighth ends in a single spine. The genital stipes is very strik- 

 ingly different from that of U-scripta Fox. 



The maculations on the paratypes vary somewhat from those of 

 the type specimen. Some specimens show a more or less well devel- 

 oped, but broken, U-shaped discal mark on the scutum, the curved 

 fascia on the median segment may be broad and conspicuous or nar- 

 row and broken ; the spots on the sides of the thorax vary in extent ; 

 the first tergal fascia may be continuous, and the fifth may be broken 

 into spots. 



Female. — Black: Labrum, mandibles except apices, clypeus except 

 median pair of black spots, scape and flagellum below, frons except 

 butterfly-shaped spot below anterior ocellus, posterior orbits not 

 prolonged on vertex, prothorax, lateral lines and broken U-shaped 

 discal mark on scutum, fascia on scutellum, fascia on metanotum, 

 broken curved fascia on dorsum of median segment, lateral angles 

 and sides of same, metapleurae and mesopleurae almost entirely, ante- 

 rior border of mesosternum, fasciae on tergites 1-4, all continuous 

 except the third and similar in design to those of the male, three spots 

 on the fifth, apex of the sixth, lateral spots on stemites 2-4, spot on 

 anterior coxae, trochanters distally, femora except a broad stripe 

 above and a short one also below on posterior pair, tibiae, and tarsi, 

 yellow. The ultimate tergite is somewhat wrinkled and is bordered 

 apically by short but well marked lateral ridges. 



Length.— 17-19 mm. 



The scape is short but not so broad as in the male. The flagellum 

 is tawny yellow below in the female but in the male it is more tes- 

 taceous. The wings are hyaline, the veins dark brown. The first 

 transverso-cubital vein is only slightly curved. The pubescence is 

 tolerably long and dense and is yellowish white in color; on the abdo- 

 men it is quite short. The ocelU and the labrum are similar to those 

 of the following species to which this species is very closely related. 



This species is described from four males in the United States 

 National Museum, three of which were collected in Texas and one 

 in New Mexico, and from one female in the collection of the Uni- 



