238 THE CANADIAN ENTOMOLOGIST 



The following key to the species includes all those occurring 

 in Central and North America. 



Key. 



1. Thorax greatly expanded laterally beyond margin of abdo- 



men and elytra. Thorax prominently con- 

 cave declivis Say. 



Thorax wider than abdomen but not greatly expanded, not 

 prominently concave , 2 



2. Dilatation of posterior tibia very small and limited to basal 



third. Inner margin of posterior tibia spinous in male. 



Femora of male greatly swollen bicoloripes Stal. 



Dilatation of posterior tibia noticeably greater, inner margin 

 of male comparatively smooth 3 



3. Outer dilatation of posterior tibia in both sexes very broad, 



widened at apex and broadly rounding latipes Drury. 



Form of dilatation of posterior tibia not as above 4 



4. Outer dilatation of posterior tibia in both sexes broad to almost 



the very tip, but not widened at apex. Large 



species granulosa Dall. 



Outer dilatation of posterior tibia not wide at or near the apex. 

 If it extends to near the apex then much narrowed 5 



5. Species small. Dilatation of posterior tibia in both sexes ex- 



tending but two-thirds or slightly more the entire length 



of tibia terminalis Dall. 



Species large. Dilatation of posterior tibia extending dis- 

 tinctly more than two-thirds the length of tibia, some- 

 times to nearly the apex 6 



6. The outer dilatation of posterior tibia of male without dis- 



tinct scallops. Hind femora of male usually greatly 

 swollen and bowed. Female broad. Thorax promi- 

 nently tuberculate femorata Fabr. 



The outer dilatation of posterior tibia of male with distinct 

 scallops. Hind femora straight and not as greatly 

 swollen. Female comparatively more narrow. Thorax 

 minutely tuberculated confraterna Uhl . 



Acanthocephala bicoloripes Stal. 

 Metapodius bicoloripes Stal., Ofv. Vet. Ak. Forh. p. 184, 1855. 



