134 HYMENOPTERA OF AMERICA. [rART I. 



Var. Scute] and metathorax with two whitish spots. 



Ress. a. diff. — The Monobia i-dens is very difficult to distin- 

 guish from the Odynerus Udens; however, one can always 

 recognize it — 1st, by its clypeus armed with two teeth %, with 

 two salienl angles ?; 2d, by its abdomen, punctured more 

 strongly and throughout, especially on the anterior face of the 

 firsl segment and upon the second which does not offer an arcuate 

 band of strong punctures along its border; 3d, by its maxillary 

 palpi which have but five articles and the labial having the 4th 

 ie rudimentary and soldered upon the third. Compare also 

 Odynerus quadrisectus. 



Hah. The United States. A species common iu all the 

 eastern pari of the country. 



I possess a greal cumber of specimens taken in all the Eastern 

 3, in New England (Norton), in Illinois (Walch, Kenni- 

 in Tennessee (Freudenreieh-Falconnet, Fuchs), in South 

 Carolina, Louisiana (author), Florida (Norton). 



B. Abdomen ovalo-conical ; the first segment more rounded, less 

 truncate, less sessile. Metathorax rounded; its concavity 

 not bordered above by trenchant ridges. 



a. On each side of metathorax a dentiform angle. 



6. M. auglllosa Sauss.— Valida, nigra, punctata; clypeo J piriformi, 

 punctato, in fere striato, subbicarinato, apice biangulato, % apice 

 truncato ; metanoto velutino, bidentato, excavatione punctata instructo, 

 nullomodo acute marginata; abdomine ovato-conico, sericeo, metanoti 

 angulis utrinque fascia lateral] aurantiaca; genibus, tibiis et tarsi s 

 prsecipue ant it is, testaceo-variis ; ali.s fusco-cyaneis. 



£ . Ant. Minis subtus ferrugiueis, scapi fascia flava ; tarsis subtus sulfureis. 



Monobia angulosa Sauss. Vespides, I, 98, G; pi. xv, fig. 5 (1852) ; III, 109. 

 Total length, 23 nun. ; wing, 18 mm. 



Large. Clypeus strongly punctured, almost in stria'; piri- 

 form, at the extremity truncate, almost biangulate. Between the 

 antennae is a kind of tubercle, grooved above. Metathorax form- 

 ing mi cadi side a compressed tooth ; the concavity a little striate 

 and punctured, but the superior edges effaced ; roughly punctured. 

 lb ad and thorax densely punctured ; the metathorax very rugose 

 above. Abdomen conical as among the true Rhynchium, shining, 

 punctures scattered; the border of the 2d segment and the fol- 

 lowing on the contrary very densely punctured, dull. 



