594 PROCEEDINGS OF THE ACADEMY OF [Au 



&•» 



Acad. Nat. Sci. Phila.). They differ very much from one another, 

 and I thought at first to separate two species, one larger, with the 

 scape yellow in front, the other smaller, with the scape dark. I think, 

 however, they are certainly all one species. The transverse medial 

 nervure is basad of the basal; a peculiar character, shared (as I learn 

 from Mr. Viereck) by N. adducta, putnami, suavis, snoivi and heilig- 

 brodtii. 

 Nomada ruidosensis, sp. n. 



6^. — Length 7 mm.; in the above table it runs doubtfully to N. 

 jragilis, with which I had confused it; it differs, however, as follows: 

 Head narrower; 'facial quadrangle almost square, not broadened above; 

 no supraclypeal mark; upper part of lateral face-marks narrower; 

 scape little swollen, dull reddish-yellow in front; flagellum (long as in 

 jragilis) more slender; third antennal joint, seen [rom above, very little 

 shorter than fourth; a small yellow spot on pleura, but no yellow on 

 scutellum: general tint of legs darker, the black more suffused; first 

 abdominal segment entirely black; yellow band on second segment 

 narrowly interrupted. The flagellum is not denticulate. 



Hah. — Ruidoso creek, New Mexico (E. 0. Wootoyi, No. 67). 



Allied to A'', dentarice, Rob., but much smaller. The basal nervure 

 meets the transverso-medial, but a little on the basad side. The sec- 

 ond submarginal cell is very broad above. The ventral surface of the 

 abdomen is dark brown, with obscure markings. 

 Nomada elegantula, Ckll. 



A new locality is Lewiston, Idaho, one in Coll. of Acad. Nat. 

 Sci. Phila., "deposited by Wm. J. Fox." 



The following species have bidentate mandibles, and belong to 

 Robertson's genus Gnathias: 



Females. 



1. Abdomen without yellow spots, 2. 



Abdomen with yellow spots, 4. 



2. Head and thorax dark; scape dark, with a red basal spot, 



perplexa, Cress., var. 

 Head and thorax lighter; scape entirely red in front, . . . 3. 



3. Mesothorax and metathorax with a black median band (Louisi- 



ana), louisiance, Ckll. 



Mesothorax and metathorax without a l)lack median band (Ne- 

 vada), -. rhodalis, Ckll. 



4. Fifth abdominal segment with yellow spots, 5. 



Fifth abdominal segment without yellow spots, 8. 



5. Lower anterior orbits yellowish; pygidium ovate; mesothorax 



commonly with three stripes, ovata (Koh.). 



