204 NORTH AMERICAN MUTILLIDAE 



10. Punctuation of the third and following dorsal segments shallow, small, 



and except on the sides sparse, the vestiture correspondingly sparse; 

 minute tubercles on the sides of the sixth ventral segment; posterior 

 ocelli separated from each other bj' three times the length of their trans- 

 verse diameter nestor Blake 



Punctuation of the third and following dorsal segments dense and not 

 shallow, the vestiture correspondingly dense; sixth ventral segment 

 unarmed; posterior ocelli separated by twice the length of their diam- 

 eter oajaca Blake 



11. Pj'gidium with a median carina which is very strongly angularly ele- 



vated some distance before the apex; sixth ventral segment simple, 

 seventh with a short oblique carina, eighth with a long low ridge on each 



side; scape of antennae not carinate navasota n. sp. 



Pygidium with a Y-shaped apical cai'ina, the two arms of the Y eml)racing 

 the abrupt termination of a median, longitudinal, raised, impunctate, 

 polished platform; scape in front bicarinate, in one species rather feebty 

 so (12) 



12. Distance of the eyes from the posterior ocelli three times as great as the 



diameter of the latter, this equal to three-fifths of their distance from 



the front ocellus rufosignata n. sp. 



Distance of the eyes from the posterior ocelli less than twice as great as the 

 diameter of the latter, this equal to or exceeding their distance from the 

 front ocellus (13) 



13. Distance of the eyes from the posterior ocelli equal to about one and one- 



half times their diameter (1.5-l.S); this about equal to their distance 



from the front ocellus hexagona Say 



Distance of the eyes from the posterior ocelli scarcely exceeding the diam- 

 eter of the latter (1.2 thereof); this equal to about one and one-half 

 times their distance from the front ocellus sayi Blake 



Females 



1. Head orange red (2) 



Head black, front sometimes a little reddish; thorax with sides nearly 



straight, slightly concave, not much widened behind, posterior face 

 squarely truncate oajaca Blake 



2. Sides of thorax very deeply emarginate, only three-fourths as wide in the 



middle as behind or in front, the width in front and behind subequal; 

 posterior face truncate; last three dorsal abdominal segments red. 



euterpe Blake 

 Sides of the thorax much less deeply, sometimes not, emarginate (3) 



3. Sides of the thorax not noticeably emarginate; thorax i)osteriorly gradually 



sloped; inferior carina of i)etiole with an anterior blunt tooth, not red at 



apex ornatipennis n. sp. 



Sides of tliorax distinctly emarginate (-1) 



4. Thorax much widened and truncate posteriorly promethea Blake 



Thorax little or no wider behind than in front (5) 



