124 CHARLES ROBERTSON. 



The male closely I'esembles female, so much so that there can be 

 no doubt to one having both sexes before him ; scape club-shaped, 

 rounded above, of same color as flagellum, third joint of latter longer 

 than fourth, apical segment of abdomen entire. 



I think the male described by Say does not belong here. This is 

 an autumnal species, and in my neighborhood flies from September 

 12 to 26. 



The two preceding species of Nomada resemble N. superha in 

 having the third joint of antenna longer than fourth, and the apical 

 segment of the abdomen in the male entire, not bifid as in many 

 other species. 



Among s])ecimens which I originally referred to N. liifeola Lep., 

 I find a number of individuals which indicate a distinct, though 

 closely allied s})ecies. The ornaments are very similar, but the struc- 

 tural characters of antennae and metathorax are quite difllerent. The 

 following descriptions indicate the more important distinctions. 



9f Oinaxla liiteola J . — Third joint of antennse shorter than fifth and nearly 

 one-half shorter tlian fourth, enclosure of metathorax roughened at base, minutely 

 "roughened beyond, large subquadrate spot on each side of metathorax extending 

 into enclosure. 



'^ . — Antennpe with joints cylindrical, not denticulate, third joint one-half, or 

 even less, as long as fourth, enclosure of metathorax roughened at base, minutely 

 so beyond. 



Nomada luteoloides 9.— Third joint of antennse shorter than fourth, 

 the latter only a little longer than fifth, enclosure of metathorax rather strongly 

 rugose throughout, spot on each side hardly subcjuadrate aud not encroaching on 

 enclosure. 



% .—Antenna} submoniliform, joints 7-10 each with an evident denticle beneath 

 near apex, third joint shorter than fourth, but not greatly so. insect black, with 

 yellow ornaments. 



i7rti>.— Illinois; two females, eight nudes. 



Nomada arfioulata Sm., Brit. Mus. Cat. Hyr.i. ii. 248; nee. Cr. Proc. Ent. 

 Soc. Phil, ii, 2!)T. 



This species resembles the nuile of preceiling. The ornaments are 

 ferruginous, except those of head and abdomen and a S})ot on pleura, 

 which are yellow ; antenii?e more moniliform, the denticles beneath 

 joints of flagellum more evident, fourtli joint a little longer than 

 third or fifth, which are sube(iual. 



