DIPLOPTERYGA — EUMENIDjE. 125 



Ahflomen sessile or sul)8essile. 

 First segment of the abdomen funnel-shaped or subeanipaiiulate. subbideiitate 

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



iVortonia Sanss. 

 First segment of the abdomen not funnel-shaped, gradually rounded or trun- 

 cate at base. 



Maxillary palpi 5-jointed ; labial palpi 3-jointed 9Ionobia Sauss. 



Maxillary palpi 6-jointed. 



L:ibial palpi 4-jointed, simple Odyiierns Latr. 



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

 First abdominal segment somewhat funnel-shaped, divided above by 

 a deep longitudinal groove ; antenme of % simple. 



Subgen. Symmorphus Wesm. 

 First abdominal segment truncateatba.se, not divided by a longitu- 

 ' dinal groove : antennae of % terminated by a hook. 



Subgeu. AncistroceruB Wesm. 

 Fii-st abdominal segment above without a transverse carina near the 



base Subgen. Odynerus Sau.ss. 



Labial palpi long and slender, 3-joiuted, the second and third joints 

 strongly compressed and bipectinate, fringed with long hairs. 



Pterochilus Klug. 

 Of the above genera Zethus and Eumenes, which have petiolate 

 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 sj)ecies are 

 referred to Emnenes, one of which, jV«/erna, 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 places an egg to- 

 gether with a provision of caterpillars tor the nourishment of the 

 larva, and then seals it up. 



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

 mon in most of the States east of the Mississippi. Nortonia is re{> 

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

 .Vtlantic States from Connecticut to Florida. 



Odipierux 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. 



Pterovhilm, which is characteri7,ed by the long, slender labial palpi 

 fringed with long hairs, is representetl by ten species, all from tlie far 

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

 to large size, and generally rare. 



