1893.] NATURAL SCIENCES OF PHILADELPHIA. 499 



The females of the first section .are generally short, robust insects, 

 while those of section II are rather long and slender and never have 

 the clypeus produced medially as in the majority of those of the first 

 section. In some respects section II agrees with Tachysphex, hut 

 the spines on fore tarsi of female are not long and flexihle, and the 

 pygidium is hairy. 



SECTION I. 



FEMALES. 



1 — Clypeus with the anterior margin in the middle, produced into a 

 large quadrate tooth or lobe, and with several smaller teeth lat- 

 erally 2 



Clypeus with the anterior margin not or scarcely produced into 



a lobe, at the most thickened in the middle 7 



2 — Metanotum strongly sulcate medially 6 



Metanotum not strongly sulcate medially 3 



3 — Third joint of antenna? about one-quarter longer than the fourth. 4 

 Third joint of antenna? equal to, or but little longer than the 



fourth 5 



4 — Thorax densely clothed with golden yellow pubescence so that 

 the sculpture of metanotum is hidden. Length 18-22 mm . . 



validus. 



Thorax s.parsely clothed with grayish pubescence; metanotum 

 finely granulated (four hind tibia? with a dark stripe within). 



Length 12-14 mm harpax. 



5 — Median process of clypeus divided into two distinct lobes; space 

 between the eyes at the top equal to the length of joints two 

 and three of antenna 1 , the latter joint, in length about equal to 

 the fourth; front and thorax with golden pubescence . prcedator. 

 Median process of clypeus not bilobed, its apex simply incurved; 

 third antennal joint slightly longer than the fourth; front and 

 thorax clothed with silvery-gray pubescence .... calcaratus. 

 6 — The sulcus on metanotum very wide; scutellum scarcely im- 

 pressed; pygidium with a coppery lustre .... mandibular is. 

 The sulcus on metanotum not wide; scutellum distinctly im- 

 pressed; pygidium silvery Or, vivt ntris. 



7 — Abdomen black 8 



Abdomen in part red; head and thorax clothed with dense silvery 



pubescence fulviventris. 



8 — Abdomen dorsally with four silvery bands; front silvery .... 9 



Abdomen dorsally with but three silvery bands; longer spur of 



hind tibia? in length about equal to the first joint of the hind 



tarsi; front golden crassus. 



9— Longer spur of hind tibia? longer than the first joint of the hind 

 tarsi; apex of femora, tibia? and tarsi, yellowish-ferruginous. . 

 columbice. 



