130 Journal New York Entomological Society. [Voi. xii. 



Smaller ; enclosure of metathorax transversely ridged ; scutellum with two yellow 

 spots rufinoda. 



7. Clypeus of female black ; pygidial plate truncate var. crucis. 



Clypeus of female white ; pygidial plate narrowed and rounded at end..crotonella. 



8. Scutellum with two light spots 9. 



Scutellum without spots 1 3. 



9. Femora black with yellow or whitish markings ; stigma piceous or brown lo. 



Femora bright reddish ; antennae very long femur-rubrum 



10. Face-markings of female yellow; abdominal bands deep yellow; punctures of 



clypeus close together; vertex without yellow spots finitima. 



Face-markings of female white or yellowish-white ; abdominal bands light 

 yellow II. 



11. Vertex with two yellow spots ; clypeus broadly bordered with black anteriorly. 



chilopsidis, 9 . 

 Vertex without such spots; black border of clypeus much shorter 12. 



12. Face broad, facial quadrangle broader than long convergens, 9. 



Face narrow, facial quadrangle much longer than broad ; punctures of clypeus 



rather sparse acanthophila. 



13. Postscutellum black ; enclosure of metathorax smooth ; clypeal space (space 



between clypeus and insertion of mandible) black eriogoni. 



Postscutellum yellow or whitish 14. 



14. Female with anterior margin of clypeus concave 15. 



Female with anterior margin of clypeus entire or straight 16 



15. The margin deeply concave, face-marks white nigrescens. 



The margin slightly concave, face-marks yellow novomexicana . 



16. Clypeus broadly truncate ; stigma piceous rinconis. 



Clypeus narrowly truncate or rounded ; stigma ferruginous vicinoides. 



In addition to the species now studied, the following have been 

 found in New Mexico : 



C. frontata Say. Vega S. Jose (Townsend), Roswell (Cock- 

 erell). 



C. venator Cr. El Rito (Townsend), Las Vegas (Cockerell), 

 Mesilla Valley. 



C. bicormita Guer. Vega S. Jose (Townsend). The last two are 

 probably sexes of one species. 



The species of Cerceris may be divided into rather artificial groups, 

 according to the sculpture of the metathoracic enclosure. The differ- 

 ences in this structure are interesting, as it is difficult to imagine in 

 what way they can be of service. 



(y4.) Enclosure without distinct punctures or stride, 

 (rt) Smooth and shining : C. ferrugimor, garciana, popu/oriii/i, erio- 

 goni, gi/ara, venato)-, californica, kennicottii, tolteca, azteca. 



