46 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 74 



MESOSTENUS PROMPTUS Cresson 



Mesostenus prompttts Cresson, Can. Ent., vol. 10, 1878, p. 209, male. Type. — 



No. 1186, Acad. Nat. Sci. Phila. 

 Mesostenus americanus Cbesson, Can. Ent., vol. 10, 1878, p. 209, female. Type. — 



No. 1170, Acad. Nat. Sci. Phila. 

 JSxetastes hrcvipennis PROvANCHEa:, Nat. Can., vol. 11, 1879, p. 213 ; Faune Ent. 



Can., Hym., 1883, p. 386, female, male. Type. — See discus.sion. 

 Mesostenus promptus (Cresson) Provancheb, Faune Ent. Can., Hym., 1883, 



p. 785. 

 Mesostenidea americana (Cresson) Vieeeck, Hym. Conn. (1916) 1917, p. 329. 

 Mesostenus in-evipennis Peovancher, Faune Ent. Can., Hym., 1883, p. 794 

 Mesostenus promptus (Cresson) Peovancher, Addit. Faune Can., Hym., 1889, 



p. 455, index. 



Discussion based on types of promptus and america/nus, notes on 

 hrevipennis by S. A. Rohwer, and three females and two males in 

 the National Museum. 



There appears to be no reason for doubt that promptus and ameri- 

 canus are the sexes of the same species, and S. A. Rohwer, who ex- 

 amined the probable types of hrevipennis, indicated in his notes that 

 Provancher was correct in synonymizing his species with promptus. 

 He writes that there are no specimens in the Provancher collection 

 under the name h7'evipennis, but that the two under protnptus appear 

 to be properly identified. 



Female. — Length, 8-12 mm. 



Temples oblique, weakly convex, polished, sparsely and weakly 

 punctate; frons and face medially densely punctate; eyes parallel 

 within; malar space subequal to basal width of mandible; antennae 

 distinctly shorter than body, flagellar joints successively gradually 

 shorter from base. Thorax more than half as deep as long, dorsally 

 polished and sparsely punctate, laterally more densely punctate and 

 sometimes largely rugulosely so, ventrally more finely and sparsely 

 punctate ; notauli fine, complete ; propodeum rugose punctate, basally 

 sparsely punctate, apical carina broadly interrupted medially ; wings 

 rather short, areolet rather shorter and broader than usual with 

 recurrent nearly interstitial, nervulus jDractically interstitial, ner- 

 vellus with upper abscissa perpendicular to cubitella; abdomen 

 slender, very finely coriaceous, first tergite polished, postpetiole 

 longer beyond spiracles than broad, second tergite fully twice as 

 long as broad at base ; sheath nearly as long as abdomen ; ovipositor 

 slender, compressed, decurved, subsagittate at apex. 



Head and thorax black, abdomen ferruginous, immaculate except 

 for a small incomplete annulus centering on flagellar joint 8 and 

 sometimes minute white spots on frontal orbits and scutellar carinae ; 

 legs black, front and middle tibiae and tarsi and hind tarsus apically 



