CERCEBIS. 



301 



52. Mesonotum not dentate ; apical 



margin of clypeus with four teeth . . C. tetradonta, p. dU4. 



b. Abdomen with the basal segment black, 



or black variegated with yellowy not red. 



a'. Clvpeus transverse anteriorlv C. sulphurea 2 , V-f^J^' 



b'. Clypeus arched anteriorly C. pictiventns, p. dOo. 



c. Abdomen with the basal segment yellow, or 



yellow with very narrow black markings. 

 a'. Clvpeus porrect, its anterior margin _ 



transverse .• C.favopicta, p. 3Ub. 



b'. Clvpeus not porrect, its anterior margin 



deeply incised C". wroughtom, p. dUb. 



B. Enclosed triangular or cordate space at 

 base of median segment punctured. 



a. Abdomen with the basal segment red. 

 a' . Clypeus emarginate anteriorly. 



a-. Apical margin of clypeus with two _ _ 



jgetb ^- instabilis J , P- "j"' • 



5^ Apical margin of clypeus not dentate. C. pulchra, p. 308. 



b'. Clypeus truncate anteriorly C. vuhnti, p. 308. 



c'. Clypeus arched anteriorly ." C. vigilans, p. .308. 



b. Abdomen with the basal segment black, or 



black variegated with yellow. 



a'. Clypeus emarginate anteriorly C. tristis, p. 309. 



b'. Clypeus arched anteriorly. . .' C. sulphurea S, V- '-'^'^• 



C. Enclosed, triangular, or cordate space at 

 base of median segment striate. 

 a. Enclosed space longitudinally striate. 

 a'. Head extraordinarily large, much 



broader than the thorax C.ferox, p. 309. 



b'. Head not extraordinarily large, not or 

 little broader than the thorax. 

 a^. Median segment posteriorly red, the 



enclosed space black C. mastogaster, p. 310. 



b"^. Median segment posteriorly red, 

 marked with yellow, the enclosed 



space black C. instabilis $ , p. 307. 



c^. Median segrment black immaculate. 



Length $ 10 mm C. unifasciata, p. 310. 



Length g 15 mm C. nebulosa, p. 311. 



d^. Median segment posteriorly black, 



marked with yellow C hilaris, p. 311. 



e*. Median segment posteriorly entirely 



fulvous C. bifasciata, p. 312. 



b. Enclosed space obliquely striate. 



a'. ;Mesostemum laterally dentate C. eUzahethce, p. 312. 



b'. Mesosternum not dentate C. pentadonta, p. 312. 



c. Enclosed space transversely striate C. kirbyi, p. 313. 



539. Cerceris albopicta, Smith, A. M. N. H. (4) xii, 1873. p. 412; 



Schlett. Zool. Jahrb. 1887, p. 485 ; Cam. Mem. Manch.L. Ph. Soc. 



(4) iii, 1890, p. 248. 



2 . Head, thorax, and abdomen closely and finely punctured ; 



the clypeus broad, flat, transverse anteriorly in the middle, 



the sides oblique, antennal carina short, broadening below ; the 



