HYMENOPTERA. 



447 



52. Cerceris bicolor. 



Female. Length 5^ lines. — The head and thorax black, the 

 legs and abdomen ferruginous ; the head and thorax closely but 

 not coarsely punctured ; the clypeus elevated from its base, 

 convex above, with a transverse yellow s])ot ; the sides of the 

 face and the carina between the antennae, yellow ; the basal half 

 of the mandibles and a minute s])Ot behind the eyes, yellow ; a 

 spot on each side of the collar, and another on the tegulsc, yellow ; 

 wings dark fuscous, with a violet iridescence. The abdomen 

 sparingly punctured, an indistinct yellow line on the apical 

 margin of the first segment. 



Hab. The Gambia. (Coll. F. Smith.) 



53. Cerceris tyrannica. 



Female. Length 5 lines. — Black and punctured : the face and 

 a large spot behind the eyes yellow, the latter forming a triden- 

 tate shape above the antennae ; the hinder margin of the vertex 

 ferruginous, with two yellow spots in the middle ; the mandibles 

 yellow and also the scape in front ; the antennae ferruginous, tips 

 of the mandibles black. Thorax : the collar, sides of the thorax 

 beneath the wings, the tegula3, scutellum, post-scutellum and 

 the sides of the metathorax, yellow ; wings hyaline, the nervures 

 ferruginous ; the apical margins w^ith a dark fuscous cloud ; the 

 legs ferruginous, with a large, ovate, yellow macula on each side 

 of the segments, occupying nearly their entire width ; the apical 

 segment yellow ; the space between the spots on the basal seg- 

 ment black ; beneath ferruginous. 



Hab. The Gambia. (Coll. F. Smith.) 



54. Cerceris fossor. 



Male. Length 5 lines. — Head and thorax black, coarsely 

 punctured ; the face ferruginous, with a yellow spot on the ante- 

 rior margin of the clypeus, and a smaller one at the anterior 

 angles of the face ; the scape yellow^ in front ; the mandibles 

 yellow, with their apex rufo-piceous. Thorax : an interrupted 

 line on the collar, a spot on the tegulae in front, the post-scu- 

 tellum, and a minute spot on each side of the metathorax, 

 yellow ; wings fusco-hy aline, with a purple iridescence, the sub- 

 cordate space at the base of the metathorax transversely striated, 

 the metathorax swollen at the sides; a yellow spot at the apex 

 of the anterior femora outside ; the tibiae and tarsi yellow, the 

 apical joints of the latter slightly ferruginous ; the intermediate 

 legs have the apex of the coxte, the trochanters, the tibiae and 

 tarsi yellow ; the posterior legs, with the coxae, trochanters, and 



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