BY ROWLAND E. TURNER. 85 



a 8 . Median segment oblique. melleus Westw. 181 



6 s . Median segment abruptly truncate. 



irritans Sm. 183 

 b s . Abdomen not banded with yellow. 

 a 6 . Abdomen ferruginous red. basalts Sm. 185 



6 6 . Abdomen black. tuber culifrons Sm. 186 



ft 2 . Abdomen fusiform or elongate-fusiform. 

 a 3 . Clypeus not emarginate at the apex. 



a 4 . First ventral segment of the abdomen with a tubercle 

 at the apex. 

 a 5 . Abdomen black, with a broad yellow band on the 



fourth segment. unifasciatus Sm. 201 



b 5 . Abdomen wholly black. 



a 6 . Abdominal segments margined with white 



pubescence. impetuosus Sm. 202 



6 6 . Abdomen without pubescence. ivaterhousei. 205 



6*. First ventral abdominal segment without a tubercle 

 at the apex. 

 a 5 . Second ventral segment of the abdomen with a 



tubercle at the base. melanotics. 203 



b 6 . Second ventral segment without a tubercle. 

 a 7 . Abdomen with broadly interrupted orange 

 bands. 

 a 8 . The abdominal segments strongly con- 

 stricted, constrictus Sm. 200 

 6 8 . The abdominal segments not much con- 

 stricted. 

 a 9 . Median segment and scutellum black. 



modestus Sm. 199 

 6 9 . Median segment and scutellum marked 

 with orange. 

 a i0 . Pronotum marked with orange on the 

 anterior margin only. 



frauenfeldianus Sauss. 198 

 b l °. Posterior margin of the pronotum 

 broadly marked with orange. 



nubilipennis Sm. 197 

 b 7 . Abdomen wholly black or black and ferrugi- 

 nous brown. 

 a 8 . Clypeus black; abdomen elongate-fusiform. 



moechus. 189 



b 8 . Clypeus yellow or margined with white at 

 the sides. 



