54 PROCEEDINGS OP THE NATIONAL MUSEUM vol.74 



ACERASTES PERTINAX (Cresson) (new combination) 



Figs. Si, 5, 6n 



Mesostenus pertitwx Ckesson, Trans. Amer. Ent. Soc., vol. 4, 1872, p. 163, 

 female. Type.— Csit. No. 1429, U.S.N.M. 



Discussion based on type and three other females, all in the Na- 

 tional collection. 



Female. — Length, 5.5 mm. 



Head polished beliind ; f rons with a weak median carina and very 

 faintly coriaceous; face, clypeus and malar space opaque coriaceous, 

 the face medially and clypeus basally minutely punctate; eyes 

 slightly convergent below ; malar space hardly as long as basal width 

 of mandible; antennae very nearly as long as body, slender, barely 

 thicker beyond middle. Thorax nearly twice as long as deep, prono- 

 tum polished, foveolate along posterior margin; mesoscutum pol- 

 ished, middle lobe sparsely punctate anteriorly and with a median 

 groove posteriorly, notauli deep and complete; scutellum polished; 

 mesopleurum striate in impression, punctate below, speculum pol- 

 ished, mesosternum finely punctate; metapleurimi more coarsely 

 punctate, upper division polished in lower angle; propodeum pol- 

 ished before basal carina, finely reticulate rugose behind, apex trans- 

 versely so, apophyses represented b}' small tubercles; nervellus re- 

 clivous, upper abscissa perpendicular to cubitella; legs slender, but 

 not so slender as in Polycyrtidea limitis, the hind femur not sub- 

 clavate. Abdomen somewhat broader than in Polycyrtidea,, very 

 minutely coriaceous, except first tergite, which is polished, postpeti- 

 ole at apex twice as broad as petiole; sheath little more than half as 

 long as first tergite; ovipositor compressed, sagittate at apex. 



Head and thorax black and yellow, more yellow than black, with 

 base of propodeum reddish piceous to ferruginous; yellow as fol- 

 lows: Head, except occiput and middle of face and frons, under 

 side of scape and first two or three flagellar joints, and a complete 

 annulus on flagellar joints 6-9; anterior and humeral margins of 

 pronotum, two elongate marks on disk of mesoscutum, scutellum 

 and its basal carinae, postscutellum ; subalar tubercle, speculum, and 

 lower half of mesopleurum; sternum (sometimes reddish); both 

 upper and lower divisions of metapleurum; and propodeum behind 

 basal carina except in anterior angles and apical middle; wings hy- 

 aline, venation brown; legs testaceous, front coxae and trochanters 

 and sometimes the other coxae more or less stramineous ; hind tarsus 

 reddish or fuscous, usually with second and third joints more or less 

 white; abdomen ferruginous, petiole somewhat paler. 



The type and one of the other specimens are from the Belfrage 

 Texas collection ; a third is from Piano, Tex., October, E. S. Tucker ; 

 and a fourth from Minatitlan, Mexico, February 1, 1892, Herbert 

 Osborn. 



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