eumen'ib.e. 331 



Tribe *DIPL0PTEEA. 

 Family EUMENIDiE. 



Tongue elongate, projecting beyond the mandibles or folded 

 back against the sternum, the median part bifid at apex and with 

 a lateral lamina surmounted by a corneous point at top of each of 

 the divisions ; head variable, wider or narrower than the thorax ; 

 antenufe geniculate or arched, stout or filiform, 12-jointed in the 

 5 , 13-jointed in the (^ ; eyes reniform, the inner orbits having a 

 sinus or emargination ; thorax broad, more or less square in front, 

 the posterior lateral angles of the pronotum reaching the base of 

 the wings ; legs generally slender and feebly armed, the intermediate 

 tibice ivith one spine at apex, the claws dentate. Wings when at rest 

 with a longitudinal fold; fore wing with one elongate radial 

 cell, and, owing to the extension of the cubital nervure to 

 the margin of the wing, four cubital cells, the 2nd cubital cell 

 receiving both, or the 2nd and 3rd cells each receiving one, of the 

 recurrent nervures, the 1st discoidal cell considerably longer than 

 the 1st submedian cell. Abdomen very variable. 



Key to the Genera. 



A. First abdominal segment long and narrowed 



into a petiole. 



a. Petiole broad and flattened in the middle, 



narrow at base and apex ; labial palpi 



3-jointed, maxillary palpi 6-jointed . . . ._ Zetuus, p. 332. 



b. Petiole not narrowed at apex ; labial palpi 



4-jointed, maxillary palpi 6-jointed. 

 a' . Mandibles long, pointed, without distinct 



teeth ; antennae inserted high up in 



the middle of the face Etjmenes, p. 333. 



b'. Mandibles short, truncate, dentate at 



apex : antennae inserted verv low down 



on the face '■ .• • Labus, p. 318. 



c. Petiole gradually widening to apex ; labial 



palpi ."{-jointed, maxillary palpi 5-jointed, 



mandibles moderately long Montezumia, p. 319. 



B, First abdominal segment not narrowed into 



a long petiole,, either pseudosessile or only 

 slightly narrowed. 

 a. Second cubital cell not petiolate. 

 a'. Labial pal])i 4-jointed, not plumed. 

 d^. Apical 3 joints of maxillary palpi 

 very small ; united, equal in length 

 to the 3rd joint Rhynchium, p. 351. 



* The 3rd and following abdominal segments in the Biploptera are strongly 

 retractile and often withdrawn after death within the 2nd segment ; therefore, 

 to insure greater accuracy, all measarements of length are from the front of the 

 head to the posterior margin of the 2nd abdominal segment. 



