THE CANADIAN ENTOMOLOGIST. 31 



Pale pronotal vittge narrower, more or less nearly half as wide as the 

 intervening dark space, distinctly dilated internally just behind the 

 middle ; third antennal joint as in IVebbi 7 



Pale vittt« relatively very narrow, much less than half as wide as the 

 intervening dark space, and never dilated internally near the middle; 

 third antennal joint more elongate, about three times as long as the 

 second and but slightly shorter than the fourth, except in simidaiis; 

 species larger in size, the elytral intervals alternating but slightly in 

 width in the females, from which sex all the descriptions are taken ; 

 minute squamules moderately close-set, forming a thin blue to 

 olivaceous bloom, very readily denuded 10 



7. Body stouter and strongly convex, the elytra feebly narrowed from the 



base to about apical thud, then more strongly, arcuately n-arrowed 

 to the tip ; sides of the prothorax arcuately shouldered anteriorly ; 



minute squamules producing a thin cobalt-blue bloom 8 



Body narrow, less convex, the sides of the elytra gradually and almost 

 evenly converging from the base nearly to the narrowly rounded 

 apex, and feebly arcuate ; minute squamules easily denuded as 

 usual, producing an olivaceous bloom as a rule, becoming blue in 

 some cases ; elytral intervals slightly alternating in width . . . . 9 



8. Strial intervals of the elytra conspicuously alternating in width toward 



tip ; lateral vittae of the pronotum and elytra pure while, the under 

 surface with a blue bloom, the hypomera with several widely 

 scattered white scales. Length {$ ) 29.0-32.0 mm.; width 9.0-10.0 



mm. Arizona (Bill Williams Fork) Snorvi, n. sp. 



Strial intervals uniform in width throughout or very nearly so ; lateral 

 vittcC yellowish-white, the under surface as m Snoivi ; elytra and 

 prothorax more elongate. Length ( ?) 30.0 mm.; width 9.0 mm. 

 Arizona (B. Wms. Fork) idoneus, n. sp. 



9. Sides of the prothorax obliquely rounded and shouldered anteriorly; 



body smaller and more slender, the abdomen simple, the fourth 

 segment ( ^ ) not at all impressed at the sides ; hypomera usually 

 with numerous white scales clustered longitudinally at the centre. 



Length 27.0 mm.; width 7.5 mm. Arizona (B. Wms. Fork) 



Arizonicics, n. sp. 



Sides of the prothorax evenly arcuate, and converging from the middle 



to the apex, the prothorax about a third longer than wide { ^J ) or 



somewhat shorter ( $ ) ; abdomen in both sexes with a ])ronounced 



and clearly limited impression at each side of the fourth segment ; 



