Horn.] 



104 



[Feb. 21, 



Group I. 



This group contains nearly all the large and imposing- species of the 

 genus, which may be arranged as follows : 



Antenna' : with joints 4—3-6 having a prolongation from 

 their upper side. 

 Middle tibiae § flattened and near the tip somewhat 



contorted eucera. 



Antenme § with joints 4 to 7 thicker than the others. 



Pygidium § prolonged and dilated at tip quadrimaculata. 



Pygidium § not dilated at tip. 

 Pygidium § elongate oval more or less acute at tip. 



Head and thorax black, thorax not pentagonal. .. melaena. 



Head and thorax red, thorax pentagonal strongly 

 angulate at the sides. 



Legs entirely red, elytra strongly reticulate magisU r. 



Legs entirely black. 



Elytra obsoletely reticulate miln&rata. 



Elytra strongly reticulate par. Cooperi. 



Pygidium § broad, truncate. 



Hind trochanter § with acute spine. 



Fifth abdominal segment § broadly emarg- 



inate, lateral lobes prominent Nuttali. 



Fifth" abdominal segment g deeply and acutely 



notched lateral lobes broadly rounded cyanipennis. 



Hind trochanter § mutic. 

 Body above not pubescent; tibiae nearly glabrous. 

 Joints 4—7 § antennae with short hairs ; sur- 

 face metallic riridana. 



Antennae not hairy ; surface of body black. 



Thorax pentagonal, sides angulate hnjubris. 



Thorax longer than wide, sides moderately 



rounded CMldii. 



Thorax broader than long, sides strongly 



arcuate tenebrosa. 



Body above pubescent ; tibial rather densely pu- 

 bescent. 

 Body above black ; thorax coarsely punctured. puberula. 



Body above in great part yellow ; thorax 

 nearly smooth, base at middle emarginate.. biguttata. 



0, eucera, Chev. Col. Mex. Centur. I, No. 56, 1834. 



Head black, impunctured, occiput rufous with narrow median black 

 line. Antennae black, joints 4-5-6 with a prolongation from their upper 

 distal angle § . Thorax black with very few fine punctures, pentagonal, 

 lateral angles not prominent. Elytra black, elongate, parallel, feebly 



