4 PROCEEDING OF THE NATIONAL MUSEUM vol. 124 



dose teeth; occipital carina complete dorsally; maxillary palpus 

 6-segmented, labial palpus 4-segmented. 



Thorax narrower than in Mesa, considerably longer than broad; 

 pronotum comparatively longer than in Mesa, the anterior portion 

 abruptly declivous and separated from posterior horizontal disk by 

 a ridge, the posterior margin arcuate; scutum slightly shorter than 

 pronotal disk, with notauli and parapsidal furrows present on pos- 

 terior three-fourths; scutellum slightly longer than scutum; post- 

 scutellum a narrow curved sclerite ; mesopleuron bulging ; metapleuron 

 flat, reduced; propodeum with distinctly differentiated dorsal, pos- 

 terior, and lateral surfaces, dorsum with a narrow, elongate, median 

 cuneate impression, lateral surface with close, weak, oblique ridges. 



Abdomen relatively broad, flattened, 6-segmented; disk of first 

 tergum ridged anteriorly; pygidial area shagreened or polished at 

 apex, not closely longitudinally striate as in Mesa. 



Wings extending to about apex of fourth abdominal tergum; mar- 

 ginal cell with outer half of anterior margin removed from wing edge, 

 the apex acute, not narrowly rounded as in Mesa, three submarginal 

 cells, the second and third each receiving a recurrent nervure; in 

 hind wing cubitus arises beyond transverse median nervure. 



Legs relatively short and stout, much less spinose than in Mesa; 

 outer surface of mid- and hind tibiae with weaker, more separated, 

 prickle-like spines than in Mesa; longer spur of hind tibia with pos- 

 terior margin rounded, not toothed; tarsal claws cleft; foretarsal 

 rake weaker than in Mesa. 



Color black, abdomen usually with strong blue reflections; head 

 red; wings strongly infumated. 



Male. — Head not porrect as in female, but much better developed 

 behind eyes than in Mesa; eye comparatively smaller than but shaped 

 as in Mesa, less strongly reniform than in Myzinum, touching base 

 of mandible; the latter similar to that of female but weaker, not 

 strongly curved as in Mesa; antennae arising from beneath frontal 

 lobes, apparently 12-segmented, pedicel mostly concealed in recessed 

 apex of scape, much shorter than in Mesa, most segments less than 

 twice as long as broad; ocelli three in number, small; clypeus much 

 as in female but median keel weaker and never strongly produced; 

 maxillary palpus 6-segmented, labial palpus 4-segmented. 



Thorax longer than broad; pronotal disk about as long as broad, 

 the sides slightly converging anteriorly, a strong ridge between disk 

 and abruptly declivous anterior portion of pronotum; scutum shorter 

 than pronotal disk, notauli and parapsidal furrows well-developed on 

 posterior three-fourths; scutellum as long as scutum; mesopleuron not 

 so strongly bulging as in female, without an anterior ridge and not 

 produced anteriorly in middle; propodeum with ridge between dorsal 



