286 THE CANADIAN ENTOMOLOGIST. 



8. False pygidiuin small ; apex of ventral segment 5 narrow ; black ; 



coxae and front trochanters black ; closely pnnctured ; fascias 



interrupted on segments 1-2 ; 12 mm.; sp. nov micropygius. 



False pygidium large 9. 



9. Pleura with an L-shaped patch ; middle and hind femora red ; fasciae 



on segments 3-4, and usually on 2, continuous; 10 mm.helianthi. 



Pleura with a lunate patch; femora usually more or less black; 

 labrum, mandibles; scape, tubercles and tegulre usually red; the 

 legs rarely black ; fasciae usually interrupted on segments 1-3, 



usually continuous on 4 ; 8-12 mm Cressonii. 



Males. 



Border of segment i hardly broader on the sides ; mesonotum 

 bilineate ; abdomen 6-fasciate 6. 



Border of segment i broad laterally, forming lunate or subquadrate 

 patches ; ornaments cream colour i. 



1. Disc of mesonotum not enclosed by a complete border 3. 



Disc of mesonotum black, subcordate, with a complete border; black. 2. 



2. Abdomen 5-fasciate, rarely a faint fascia on segment 6 ; the bands 



continuous, that on 2 suddenly widened on the sides ; scutel flat, 



spines nearly obsolete ; 13-16 mm Nevadensis. 



Abdomen 6-fasciate, bands interrupted on segments 1-2, gradually 

 widening on sides of 2, cinereous on 6 ; 10-15 mm. . . .remigatus 



3. Mesonotum anteriorly with a broad band ; abdomen 5-fasciate, 



segment i with fascia continuous or interrupted, 2-5 with continu- 

 ous fascias wider on sides of 2-3 ; black ; 12-15 nnH' • .concavus. 

 Mesonotum bilineate 4. 



4. Abdomen 5-fasciate, bands continuous or interrupted on segment i, 



continuous on 2-5, cinereous on 4-5 ; black patch on segment 1 

 transverse subquadrate ; black, labrum, mandibles, base of 

 antennae, tegulse, tibiae, tarsi and pygidium more or less tinged 



with red ; 1 2 mm simplex. 



Abdomen 6-fasciate, bands interrupted on segments 1-2, sometimes on 

 3, cinereous or whitish on 5-6 ; black patch on segment i usually 

 triangular ; 10-13 mm 5. 



5. Labrum, mandibles, joints 1-3, tegulse and legs red lunatus. 



Labrum, mandibles, joints 1-3, tegulse and legs black ..... .concolor. 



6. Ornaments cinereous; fasciae usually interrupted on segments 1-2, 



white on 6 ; black ; 9-12 mm donatus. 



Ornaments cream colour ; tibiae and tarsi usually red 7. 



