284 THE CANA.DIAN ENTOMOLOGIST. 



First joint of the flagellum a little longer than the second ; more than one- 

 half of the pleura yellow . . . . : Edwardsii. 



Similar to Edwardsii in the length of the antennal joints ; only a spot of 

 yellow on the pleura, the spot at the anterior inferior corner ; very like 

 HempJiilii, the yellow of the scutellum reduced to two spots ; seventh 



segment entire vinnula $ . 



Holonomada vintiula (Cress.). — Tr. Am. Ent. Soc, VII, 202, 1879, 



May be only a race of Edwardsii, or perhaps only a mutation. 



Corvallis, Or., i-io June. (Cordley.) 



Holonomada Edwardsii (Cress.).— Tr. Am. Ent. Soc, VII, 72, 

 1879, $. 



Corvallis, Or., 3rd April, nth May, June (Cordley). Washington 

 (A. E. S. P.). 



Holo7ioinada suavis (Cress.). — Tr. Am. Ent. Soc, VII, 74, 1879, 

 9 6- 

 . Oregon (A. E. S. P.). 



Xanthidium, Robt. 

 Third joint of the antennas subequal with the fourth : posterior orbital 

 margin yellow, mesothorax black, with or without stripes ; face 

 broader than long ; lateral face-mark receding from orbits above ; 



end of flagellum black above citri?ia. 



Lateral face-marks not receding from orbits civilis. 



Joint three longer than four Cordley i. 



Joint three shorter than four , 1 . 



1. Scutellum black modocorum. 



Scutellum red libatutn. 



Scutellum yellow or spotted with yellow 2. 



2. Basal nervure meeting the transverse medial nervure 3. 



Basal nervure ending distinctly basad of the transverse medial nervure. 4. 



4. Legs yellow and black, sometimes with a red suffusion, especially 



toward the base ; apex of abdomen notched, though sometimes 

 obscurely ; legs with red if any 5. 



5. Pleura with a large transverse yellow patch 6. 



Pleura with a smaller yellow mark below tubercles 7. 



6. The yellow patch not divided in the middle ; scutellum with two 



yellow spots ; mesothorax all black rivale. 



7. Lateral face-marks continued narrowly to top of eye ; flagellum not 



denticulate; tibia? yellow,""with a black spot behind civile. 



