THE CANADIAN ENTOMOLOGIST. 175 



4. Joint 3 shorter than 4 ; vein a interstitial witli V,, ; abdomen red, with 



whitish ornaments Pluu-. 



Joint 3 longer than 4 ; abdomen black, with yellow 



ornaments Holonomada. 



5. Vein rm usually wanting ; segments 1-6 with yellow bands, that on i 



usually red Hcininomada. 



Vein rm rarely wanting 6. 



6. Segments 1-6 with entire and continuous bands, sometimes narrowly 



interrupted on i ; vein a before Vg Xanthidiuvi. 



Segments 1-6 without entire and continuous bands, usually with some 

 lateral spots ; when continuous, the bands have separated spots on 

 extreme sides of 5 Nomada. 



Gnathias, gn. nov. (Type Nomada be/la, Cresson). 



Females. . 



Pygidium ovate, rather closely punctured and pubescent ; lower an- 

 terior orbits yellowish ; mesonotum commonly trilineate ; rather yel- 

 lowish red, the spots small and hardly contrasting with the ground 



colour ovatus, sp. nov. 



70 specimens fall into the following forms, according to their colour 

 patterns. The ornament on the side of segment 4 is counted as one 

 spot. It consists of an elongated spot, or its representatives: (i) 

 when the spot is broken in two, or (2) when the lateral portion dis- 

 appears, leaving a subdiscal, more or less cuneate spot. 

 A spot on each side of segments 2-4 and a bar on 5 (10) . . . .plenus. 



A spot on each side of segments 2-5 (15) odomaculattis. 



A spot on each side of segments 2-4 (r), or of 2, 3 and 



5 (2) sexmaculatus. 



A spot on each side of segments 2-3 (15), or of 2 and 



5(3) quadrwiaculatus. 



A spot on each side of segment 2 (22) binotatus. 



Abdomen without spots (2) tmicolor. 



Pygidium triangular, sparsely puncttired and pubescent ; lower anterior 

 orbits not yellowish ; mesonotum one-lined ; rather dark red ; spots 



distinct, large on segment 2 cuneaius, sp. nov. 



28 specimens show the following forms, the ornaments of segment 2 

 as in the preceding : 



A spot on each side of segments 1-5 (i) decemnotatns. 



A spot on each side of segments 2-5 (15) octonotatus. 



