

HYMENOPTERA. -431 



6. MlMESA MELLIPES. 



Psen? mellipes, Say, Bost. Journ. i. 369. 1. 

 Hab. N. America (Indiana). 



7. MlMESA BOREALIS. B.M. 



Male. Length 2| lines. Black : the head shining and finely 

 punctured on the vertex, the face with a thin silvery pubescence ; 

 the antennae clavate ; tips of the mandibles ferruginous. Thorax 

 shining and punctured, sparingly pubescent above, more thickly 

 so on the sides and beneath, the pubescence of a silvery bright- 

 ness ; the metathorax very coarsely rugose ; the tarsi pale rufo- 

 testaceous ; the wings hyaline and iridescent. Abdomen very 

 smooth and shining, beyond the first segment thinly covered 

 with short silky pubescence; the petiole with a longitudinal 

 central carina, its apex acuminate, and having a central channel 

 running from the base to the apex. 



Hab. Hudson's Bay. 



This species closely resembles the M. unicolor, but the antennae 

 are much more clavate; the metathorax is also much more coarsely 

 sculptured. 



S. MlMESA ANTENXATA. B.M. 



Female. Length 4^ lines. Black : the head smooth and 

 slightly shining ; the face and mandibles densely covered with 

 silvery pubescence ; the clypeus produced, with an obtuse tooth 

 in the middle ; the mandibles ferruginous at their apex ; the 

 antennae longer than the thorax ; the flagellum very slender at 

 the base and much thickened at the apex ; the cheeks armed 

 with stout curved spines. Thorax smooth and shining; the 

 metathorax rounded behind, with a central impressed line in the 

 middle which runs upwards to the verge of the truncation ; 

 wings hyaline, slightly clouded at their apex; the pectus and 

 femora beneath covered with glittering silvery pubescence. 

 Abdomen : the petiole narrowed towards the base ; the abdomen 

 very smooth and shining; the apical segment margined at the sides. 

 and covered with scattered punctures and short glittering hairs. 



The male closely resembles the female, but has the antenna? 

 less thickened at the apex. 



Hab. Sandwich Islands. 



Genus 10. DIODOXTUS. 



Crabro, pt., Fabr. Ent. Syst. ii. 293 (1793). 

 Pemphredon, pt., Fabr. Syst. Piez. 314 (1804). 



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