728 PROCEEDINGS OF THE ACADEMY OF [NoV., 



HYMENOPTERA FROM SOUTHERN CALIFORNIA AND NEW MEXICO, 

 WITH DESCRIPTIONS OF NEW SPECIES. 



BY H. VIERECK. 



This paper is the result of a study of material collected in the 

 year 1901 and received for identification from Prof. Cockerell. 

 Unless otherwise stated, he is the collector of the specimens under 

 consideration. 

 Melissodes montana Cress. 



Three ? ?, 10 to 12 mm. in length. The abdominal fascise 

 vary from ochreous to whitish. 



San Pedro, July 4, 11, 



Specimens in the Coll. Am. Ent. Society represent the originals 

 only and are from " Colorado" and " New Mexico" (Cresson 

 Coll.). 



One cJ*, La Jolla, August, has the dorsum of thorax covered 

 with an ochraceous pubescence. The clypeus is aU yellow, a black 

 dot on each side. « 



Diadasia rinconis opuntiae Ckll. (Det. Ckll.). 



San Pedro, July 27, at flowers of Opuntia. 



Diadasia australis Cress. 



One d', San Bernardino, July 6, on sunflower. Specimens in 

 Coll. Am. Ent. Society represent only " Colorado" and "Texas." 

 Nomada formula n. sp. 



Black, max'ked with yellow ; apex of wings cloudy ; metathorax 

 with a bare, satiny, triangular area. 



?. — Length 8 mm. Labrum closely indistinctly' punctured. 

 Clypeus closely punctured, the yellow area above clypeus and the 

 yellow areas on the sides of the face more distinctly punctured, the 

 punctures a little wider apart. The black part of the head closely 

 distinctly punctured. Cheeks dullish, indistinctly sculptured. Head 

 covered with a fine silvery pubescence, not so heavy as to obscure any 

 characters. First joint of flagellum at least one-fourth longer than 



