24 Myron Harmon Swenk 



A. palliventre Cresson as its unknown male, at least it is so far 

 as the specimen from Logan, Utah (L. Bruner, No. 17) is con- 

 cerned. The series of six males before the writer, one of which 

 bears the Bruner No. 17, are accompanied by two females which 

 are not palliventre, but differ at once in the yellow-spotted face 

 and clypeus, yellow tubercles, yellow lines on mesoscutellum, and 

 broad yellow lines on tibiae externally (these parts black in 

 palliventre) , the lack of a yellowish tinge on the pubescence of the 

 head and thorax (present in palliventre) , the reddish hair of hind 

 basitarsi within (black in palliventre), etc. It is close to A. 

 emarginatum (Say) and A. astragali, just described, but differs 

 from both in the yellow spot on mandibles and yellow spots on 

 the clypeus and face in the female, and in the immaculate meso- 

 scutellum, triply interrupted bands of tergite 2 and often of 3, 

 and quite differently shaped pygidial lobes in the male. It is also 

 close to A. tenuiflorae Ckll., but differs in the yellow markings on 

 clypeus and face, mandibles, mesoscutellum, tubercles and tibiae 

 in the female, while the male is chiefly distinguishable by the 

 shorter and broader pygidial lobes, the deeper yellow abdominal 

 bands which are broken into four spots on tergite 2 and often on 



3 as well as on i, etc. From A. maculosum Cresson, it differs in 

 the yellow spots on face, yellow stripes on tibiae, bands on tergites 



4 and 5 interrupted only medially, etc. 



Genus Dianthidium Cockerell, 1900 



KEY TO THE NEBRASKA SUBGENERA 



Pulvilli large ; second recurrent nervure received well beyond the second 

 transverse cubital nervure, rarely only a little beyond it; maxillary 

 palpi 2-jointed; mandibles 3 or more dentate; smaller species with 

 usually distinctly interrupted abdominal bands. 

 Hind edge of mesoscutellum not greatly produced or sharp-edged; 

 hind coxae of male usually spined ; more slender species. . Dianthidium 



(Type D. sayi Cockerell) 



Hind edge of mesoscutellum much produced and sharp-edged, the 



yellow marks on it in a straight line or nearly so; hind coxae not 



spined ; small and very compact species Anthidiellum 



(Type D. strigatum Panzer) 

 Pulvilli small; second recurrent nervure usually opposite the second trans- 



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