Studies of North American Bees II 



Only a small yellow spot or band behind the eyes I 



I. Lobes of the pygidium long and terminating in an inwardly directed 

 tooth; pygidium wholly black; mesoscutellum usually with two 

 yellow lines ; first abdominal tergite with two large lateral and 



usually two small discal spots ; 12 mm psoraleae 



I. Lobes of the pygidium evenly rounded, their apices not distinctly 



produced and directed inwardly 2 



2. Venter red; pygidium usually red, and sometimes the whole of tergum 



red (variety amabile Ckll.) ; 13-15 mm porterae 



2. Venter and pygidium black, the latter sometimes yellow spotted 3 



3. Mesoscutellum black; scape black or with a small yellow terminal 



spot 4 



3. Mesoscutellum with two linear spots 5 



4. Middle and hind tibiae with large triangular yellowish apical areas as 

 well as knee spots; band on first abdominal tergite reduced to small 

 lateral spots sometimes with minute middle dots between; 11-12 mm. 



nehrascense' 

 4. Middle and hind tibiae black except for the small yellow knee spots ; 

 first abdominal tergite always distinctly four spotted; 9-1 1 mm. 



tenuiflorae 

 5. Scape black; hair of thorax only slightly if at all tinged with 

 ochreous; lobes of pygidium rather narrowly rounded; 10 mm. 



emarginatum 



5. Scape with a broad yellow stripe in front; hair of thorax above 



strongly tinged with ochreous ; lobes of pygidium broadly rounded ; 



9-10 mm astragali 



(The male of clypeodentatum is unknown or unrecognized.) 

 Anthidium serranum Cockerell. 



1904. Anthidium serranum Cockerell, Bull. Sou. California Acad. Sci., 

 Ill, pp. 23-24, (^. 



A single female specimen before the writer labeled simply 

 " Nebr. ? " evidently belongs here rather than with illustre Cres- 

 son because of the color of the thoracic pubescence, which is 

 white rather than fuscous ; otherwise it agrees with Cresson's 

 description of the female of illustre. It is extremely doubtful 

 that this specimen was captured in Nebraska, as the known range 

 of the species of this group, A. illustre, serranum, conspicuum, 

 etc., is confined to California and Nevada, and it is most likely 

 that the specimen came from the former state. It has seemed 

 best, however, to include the species in the list with this expla- 



1 1 



