DIPLOPTERYGA — EUMENIDilS. 125 



Abdomen sessile or subsessile. 



First segment of the abdomen fnnnel-sbaped or siibeamiianiilate, sulibidciittite 

 in the middle ; maxillary paljii 6-jointed, labial jialjti 4-jointed. 



N^orloiiia Saiiss. 

 First segment of the abdomen ntit funnel-shaped, gradually roimdcd or trun- 

 cate at base. 



Maxillary paljii o-jointed ; labial pali)i 3-jointed .. Moiiobitl Sauss. 



Maxillary palpi 6-joiuted. 



Labial palpi 4-jointed, simple Ortyiieriis Latr. 



First abdominal segment above with a transverse carina near the base. 

 First abdominal segment somewhat fuunel-shaped, divided above by 

 a deep longitudinal groove ; autennse of % simple. 



Subgeu. Symmorphus Wesm. 

 First abdominal segment truncate at base, not divided by a longitu- 

 dinal groove ; autennge of % terminated by a hook. 



Subgen. Ancistrocerus Wesm. 

 Fir.st abdominal segment above without a transverse carina near the 



base Subgen. Odynerus Sauss. 



Labial palj)! long and slender, 3-,jointed, the second and third joints 

 strongly compisessed and bipectinate, fringed with long hairs. 



Pterocliilus Klug. 



Of the above genera Zethus and Eumenes, which have petiolatc 

 abdomen, are easily separated by the form of the head. The former 

 genus, so abundant in species in tropical and subtropical America, 

 has but one representative in our fauna. In the list six species are 

 referred to Eumenes, one of which, fraterna, is widely distributed and 

 common ; it constructs a spherical nest of fine yellowish clay, which 

 may often be found adhering to leaves, small twigs, or fastened 

 against walls ; within this little s])here, the insect ])laces an egg to- 

 gethei- witli a provision of caterpillars for the nourishment of the 

 larva, and then seals it up. 



Of Moiiobia we have two species, one of which, qaadrldens, is com- 

 111(111 in most of the States east of the Mississippi. Nortonia is rep- 

 resented by one species, of rather rare occurrence, and found in the 

 Atlantic States from Connecticut to Florida. 



Odynerus has numerous species, widely distributed over the coun- 

 try ; they are divisible into several subgenera, the characters of which 

 are given in the above table ; many of the species are ornate with 

 gay colors, and make a very pretty collection. 



Pfenx-hilus, which is characterized by the long, slender labial palpi 

 fringed with long hairs, is represented by ten s})ecies, all from the far 

 Western States; they are gaily colored, handsome insects, of medium 

 to large size, and generally rare. 



