Studies of North American Bees 67 



etc., and from the latter in the yellow tegulae, more yellow on 

 legs, first abdominal tergite without clear red but with a broad 

 and only slightly medially interrupted yellow band, complete 

 yellow bands on tergites 2 and 3, white hair of mesonotum, etc. 

 Apparently, we have here either an exceedingly variable species 

 in the female, or else several species are being badly confused. 

 The writer feels certain that the females here included belong 

 wuth the males, and that the males are referable to A^. civilis 

 Cresson. The females, then, will be described as a fourth 

 variety of eivilis $: 



$. Length 8-9 mm. Black ; the clypeus, labrum, mandibles except 

 tips, lateral face marks extending narrowly along orbits to their summits, 

 line under eye extending along posterior orbits nearly to summits, collar, 

 tubercles, irregular spot beneath, tegulae, sometimes four lines on meso- 

 scutum, lobes of mesoscutelkmi, line on metanotum, spots on sides of 

 propodeum which sometimes unite with smaller spots on enclosure, a 

 broad, narrowly medially interrupted band on tergite i, a similar complete 

 but medially narrowed band on 2, complete bands of uniform width on 

 3-5, broad bands on sternites 2-4 and spots on sides of sternite 5, all the 

 knees and a broad line on outer face of tibiae, bright lemon yellow. 

 Supraclypeal area, edges of orbital lines more or less, edges of spots below 

 tubercles and on sides of propodeum more or less, apical margins of 

 the tergites and posterior edges of the bands with the interrupted spot 

 on band of tergite i, together with the legs except the yellow areas men- 

 tioned and black areas on posterior face of coxae, trochanters and femora 

 and a stripe on posterior tibiae, red. Antennae red, heavily suffused with 

 dusky beyond the third joint beneath, blackish above, joint 3 two-thirds 

 as long as 4. Head and thorax coarsely and strongly punctured, abdomen 

 indistinctly punctured. Wings hyaline, very faintly clouded on apical 

 margin, nervures yellowish brown, stigma reddish brown, basal nervure 

 basad of transverso-medial nervure. Hair of occiput, mesonotum, sides 

 of propodeum, etc., white, not tinged with reddish. 



Material. — Sioux county, Nebraska, ^Nlay (L. Bruner), 3 $. 



Nomada (Heminomada) citrina fiavomarginata n. subsp. 



A pair from West Point, Nebraska, the female of which is 

 obviously referable to the sul phnrata- perivincta-citrina group, is 

 before the writer. A study of the known forms of this confus- 

 ing group would seem to indicate that they may be divided into 

 at least three well-defined sections, each section being probably of 



67 



