NO. 20yo. THE URACONID SUBFAMILY OPIINAE—GAHAy. 67 



5. First and second abdominal tergites with a median carina; second abscissa of radius 



not longer than the second transverse cubitus Stiropiits Cameron. 



Second tergite always without a median carina; second abscissa of radius usually- 

 longer than the second transverse cubitus 6. 



6. Face with two stout horns Cephaloplites Szepligeti. 



Face without horns 7. 



7. First cubital cross vein thicker than the other veins Aiistroopiiis Szepligeti. 



First cubital cross vein normal 8. 



8. Radius arising from the extreme base of the stigma Eurytenes Foerster. 



Radius arising distinctly beyond the base of stigma 9. 



9. Abdomen subpetiolate, the first tergite at least three times as long as broad; sub- 



discoidal nervure arising from the upper angle of the second disco idal cell; second 

 cubital cell short, the second radial abscissa scarcely longer than the second 



cubital crossvein Hedylus Marshall. 



Abdomen subsessile or sessile, the first tergite not three times as long as broad; 

 subdiscoidal nervure arising at or below the middle of the second discoidal cell; 

 second abscissa of radius longer Opius Wesmael. 



Genus ADEMON Haliday. 



This genus is characterized by the completely margined occiput, 

 the open radial cell, and the rugulose sculpture of the body. The 

 recurrent nervure joins the first cubital cell some distance before the 

 basal nervure, the second abscissa of radius is about equal to the 

 first cubital cross vein, and the stigma is rather long and narrow. 

 Ashmead placed the genus in his tribe Rhyssalini, but both Marshal 

 and Szepligeti have placed it with the Opiinae. The ^vriter doubts 

 its aflBnity with the Opiinae, but has included it here for want of a 

 better understanding of its relationship. 



ADEMON NIGER Ashmead. 

 Rhyssalus niger Ashmead, Bull. 111. St. Lab. Nat. Hist., vol. 4, 1895, p. 276. 



Male. — Length 2 mm. Head, thorax, and abdomen to apex of 

 third segment finely coriaceous and opaque; head transverse nar- 

 rowed behind, the posterior orbits receding and broader than the 

 width of the eyes ; face rugose, the clypeus smooth, less than twice as 

 broad as long and apphed close to the mandibles ; occiput concave, the 

 occipital carina prominent; vertex behind the ocelli with a small 

 subtriangular smooth area bounded by sharp carinae ; antennae very 

 slender, 24-jointed, the first flagellar joint much longer than the second 

 and following joints; mesoscutum with the parapsidal grooves effaced 

 except anteriorly; mesopleurae with a crenulate impression below 

 propodeiun irregularly rugose with a median longitudinal carina; 

 wings longer than the whole body, the stigma long and narrow; legs 

 very long and slender; abdomen ovate, about as long as the head and 

 thorax, its first tergite much wider at apex than at base; sutm'iform 

 articulation distinct, the third segmnet not half as long as the second ; 

 apical segments smooth. Body color brownish-black; antennal pedi- 

 cel, mandibles, all coxae, and all femorae yellow; apices of femorae, 



