THE CANADIAN ENTOMOLOGIST. 189 



Prothorax more or less triangular, or campanulate, widest at base. .2. 



Prothorax nearly quadrate, or else more or less rounded or subcam- 

 panulate, usually constricted in front and behind, hind angles not 

 prolonged 23. 



2. Hind angles of prothorax prolonged 3. 



Hind angles not prolonged 16. 



3. Very large species (1.20 in.), prothorax strongly narrowed from the 



base, which is broadly but deeply bisinuate, posterior transverse 

 impression distinct. Elytra widest at base, gradually narrowed 

 behind, truncate and emarginate at tip, which is not margined. 

 Black with velvety pubescence, elytra red, apex black, antennae 



feebly serrate, elytra not sulcate emarginaia, Fabr. 



Small or moderate sized species 4. 



4. Prothorax without distinct transverse basal impression. Small 



species, elytra sub-parallel at sides, not spotted nor banded, but 

 uniformly dark. Prothorax often red, hind angles usually small. 10. 

 Prothorax with transverse basal impression often deep. Moderate 

 sized species, elytra usually narrowed behind, often very much so, 

 and frequently spotted, striped or banded • • • 5- 



5. Prothorax convex, with the sides much rounded in front of the 



middle, a transverse depression at base, hind angles small. Elytra 



black and yellow .... 14. 



Prothorax with sides not much rounded in front of the middle 6. 



6. Prothorax strongly narrowed from the base, usually regularly so. . . 7. 

 Prothorax subcampanulate, transverse basal impression deep, hind 



angles broad, laminate, fourth joint of antennae shorter than usual, 

 elytra not banded nor spotted 15. 



7. Elytra black or testaceous with black tip. Abdomen with the third, 



fourth and base of fifth ventrals red. Prothorax finely punc- 

 tured. .48-. 5 2 in plebej'a, Rand. 



Elytra with black and red or yellow markings ... 8. 



8. Antennae annulate 9. 



Antennae not annulate. Black, elytra very dehiscent, and not nar- 

 rowed behind, coarsely punctured, sides of elytra, metathorax and 

 abdomen red, thighs red with black tips. .36 in. .criietitata, Hald. 



9. Female reddish-yellow, varied with black beneath, legs more or less 



black ■} above with top of head, a discal thoracic stripe or spot, 

 scutellum, sutural and side margins and transverse sub-median 

 elytral band, black. Male black, base of legs and discal elytral 



