566 PROCEEDINGS OF THE ACADEMY OF [Aug., 



medial; abdomen dull, not appreciably punctured, but very minutely 

 roughened; apical margins of segments subhyaline brownish, this 

 broader in the middle than at the sides; basal half of first segment 

 black, the other half (except the margin) yellow, but the black sends 

 a straight narrow band into the yellow in the middle line, extending 

 about three-fifths the breadth of the yellow; there is also a sublateral 

 small black spot on the yellow on each side near the hind margin, the 

 same being repeated also on segments 2 to 5, which are similarly orna- 

 mented with yellow, except that the black invades it more in the 

 middle line, the yellow on segments 2 to 4 being interrupted in the 

 middle line ; on segment 2 the black also sends a short tongue into the 

 yellow at the sides ; this description does not well indicate the compli- 

 cated pattern, but it may be added that if the abdomen is viewed with 

 the apex directed upward, the yellow on segments 2 to 4 has on each 

 side a recognizable resemblance to the head of a bird ; apical plate dark 

 brown, deeply bifid; venter yellow, first segment with longitudinal 

 black bands, third and fourth segments black at base; mesosternum 

 with a large yellow patch. 



Hab. — "So. Cal.," one in Coll. Acad. Nat. Sci. Phila. A very dis- 

 tinct species. 

 Nomada (Xanthidium) sanctaecrucis, sp. n. 



(^. — Length about 8 mm.; rather slender, black and yellow. Head 

 and thorax with little hair ; facial quadrangle about square ; mandibles 

 except apex, labrum, clypeus, supraclypeal mark, lateral face-marks 

 (rather broad, ending obtusely at level of antennae), and stripe under 

 eye extending about half-way up posterior orbits, all lemon-yellow; 

 the black between the supraclypeal and lateral marks is broad, and 

 sends a narrow tongue half-way down sides of clypeus; scape mod- 

 erately swollen, yellow in front, black behind; flagellum long, ferru- 

 ginous beneath, blackish above, ordinary in structure; third antennal 

 joint about half length of fourth; mesothorax entirely black, coarsely 

 and very densely punctured; upper border of prothorax, tubercles 

 (except black dot), tegulse, irregular (with a point directed upward and 

 a longer one posteriorly) transverse patch on pleura, and two large spots 

 on scutellum, deep yellow; postscutellum and metathorax entirely 

 black; legs yellow, coxse mostly black, femora black above except at 

 apex; the first four femora, seen from behind, are longitudinally di- 

 vided into black and yellow areas, but the hind femora are all black 

 behind except at apex ; anterior and middle tibiae stained with blackish 

 behind, hind tibiae very dark brown behind except narrow upper bor- 

 der; middle and hind tarsi largely suffused with brown; wings brown- 



