132 HYMENOPTERA OP AMERICA. [PART I. 



B. Metathorax not bispmose. 



a. Metathorax with rough angles. 



3. yt. silvatica Sadss. — Nigra, punctata; clypeo apice truncato; 

 uietathoiacia cantbis rugosis hand acutis ; abdoinine sessili, basi trun- 



i, prime- segmento sec undo sequilato, secuudi margine subcanaliculatc 

 it vaMe puuetato; mandibulis, macula, froutali et post-oculari, clyp«o, 

 auteunis basi, pronoto, tegulis maculisque 2 scutelli, ferrugineis ; abd. 

 1° segmento repande flavo-limbato; pedibus tiavis, basi nigris ; alis 

 fusco-violascentibus. 9 . 

 Variat. Corpora plus luiimsve flavo-variegato. 



Monobia sylvatica Sauss. Vespides I, 93, 1 ; pi. xv, fig. 7, 9- 



Jlnb. Brazil. (Typus in rans. Parisiense.) 



This insect closely resembles Rhynchium (Odynerus) dorsale, 

 but it is somewhat .-mailer. The species seems to be distinct 

 from this, and I made some confusion with it in my Vespides III, 

 p. 168. — Compare Odyn. dorsalis, page 2G0, Obs. 



b. Metathorax rounded, unarmed. 



4. >I. aiDOitiula Sadss. 



Monobia anomala Sauss. Vespides, I, 9G, 3; pi. xv, fig. 4 (1852). 



Hab. Brazil. (Typus in mus. Dom. Guerin Meneville.) 



Division II. 



Labial palpi composed of three articles; the 3d carrying at its 

 extremity a 1th rudimentary article, soldered to the 3d, difficult 

 to distinguish, embodied with it, and armed with stiff hairs like 

 the extremity of the 3d. 



A. Abdomen conical; the 'first segment wide and. truncate. 

 Hinder portion of the metathorax bordered by trenchant 

 ridges and armed on car// side with a dentiform angle. 



This type establishes the transition to Odynerus from the 

 subgenus Odynerus, properly called, to Rhynchium, by its 

 quadrate thorax and its conical abdomen. 



5. ]tl. quail ridcus Linn. — Valida, nigra, capite et tborace valde 

 punctatis; clypeo piriform], apice £ bidentato, 9 biangulato; abdo- 

 mine conico; pronoti maculis '.!. post-scutello et abd. priino segmento 

 supra, albidis ; % minor, clypeo albido. 



