98 Myron Harmon Sivenk 



reddish to testaceous, tergites 2-6 with pale yellowish bands, mostly 

 liroad and all complete but slightly incised medially with red on anterior 

 margin of 2-4, deeply emarginate on posterior margin laterally on 4-6. 

 Venter red, a large triangular black mark on sternite i. Apex narrow, 

 subentire or at most exceedingly vaguely notched. 



Type. — Ute creek, Costilla cotinty, Colorado, June 27, 1907 

 (R. W. Dawson), ?. 



Allotype. — Type locality, June 22, 1907 (R. W. Dawson), (^. 



Paratypes. — Type locality, June 24, 1907 (L. Bruner), 3 $ ; do. 

 (H. S. Smith), 2 $; do., June 27 (L. Bruner), 3 $; do. (R. W. 

 Dawson), 2 $; do., July 3 (L. Bruner), 4 $; Russell, Costilla 

 county, June 25, 1907 (L. Bruner), i 5. 



The male of utensis agrees very closely with the description of 

 A' . ciisteriana CklL, but the third antennal joint is fully two-thirds 

 as long as the fourth ( " much shorter " than the fourth in 

 custeriaua), the apical plate is subentire (distinctly notched in 

 custeriana), the second stibmarginal cell is narrow (broad in 

 custeriana), the bands on abdominal tergites 2-4 are complete 

 (interrupted by red medially in custeriana), the malar space is 

 black (red in custeriana). etc. They are very close, however, 

 and were at first thought to be conspecific. The female agrees 

 with N. siouxe)isis, N. rhodalis and A^. louisianae in the lack of 

 yellow spots on the abdomen, but the black head and thorax 

 distinguish it at once from all of these species, which have the 

 thorax mostly red ; it is also a smaller species than these, and 

 has more black at the base of the abdomen. From A^. perplexa 

 it differs in the black head and thorax, the bright red antennae, 

 the different shape of the black abdominal marks, etc. The male 

 differs from all the other species, except custeriana, in the wholly 

 black head and thorax. 



Nomada (Gnathias) rhodomelas Cockerell. 



1903. Nomada rhodomelas Cockerell, Proc. Acad. Nat. .Sci. Phil., p. 

 595 and p. 598. ^ (??). 



A male from Vancouver, British Columbia, May 23, 1902 (R. 

 V. Harvey, No. 425), seems referable here, at least provisionally, 

 but differs from the description of the unique type of rhodomelas 

 in larger size ( to mm. long), in having the clypeus almost wholly 



98 



