810 BULLETIN 4r>, TINITKD STATES NATIONAL MUSEUM. 



or nearly so. Thorax with distinct furrows posteriorly, the ini(l<lle lobe 

 prqioctiug- slightly n])on tho bascoftlie high, convex scutelluni, tbveated 

 on either side. Wings hyaline, ])nbescent. Abdomen conically ixvinted, 

 longer than the head and thorax together, the petiole striated, scgiucnts 

 3, 4, and 5 with a transverse row of punctures. 



S . Length, 0.8 to 1""". Agrees with the 9 , except the antennje are 

 quite different, the club being .^-jointed, dilated or thickened toward the 

 tip, the joints, except the last, being tiansverse, the funiclar Joints 1 and 

 2 subequal; the abdomen broadly ovate, not longer Ihan the head and 

 thorax together, its broadest part being wider than the thorax, the 

 I)etiole and the base of second segment beneath with a tuft of woolly 

 pubescence. 



Habitat. — District of Cohimbia and Arlington, Va. 



Types in Coll. Ashmead. 



Described from many specimens. 



Polygnotus alnicola. sp. uov. 



9 . Length, 1.20'"'". Black, shining; hea<l 3^ times as wide as long 

 antero-posteriorly, the vertex posteriorly transversely aciculated, the 

 facesmot>th, polished. Antennae 10 Jointed, dark brown; pedicel longer 

 than the first and second funiclar Joints together, pale brown; tirst 

 funiclar joint very minute; second a little longer than thick, third not 

 longer than thick ; chd) o-Jointed, the first joint a little longer than wide, 

 slightly narrowed toward bast', the second, third, and fourth quadrate, 

 the last ovate, longer than the preceding. Thorax ovoid, polished, the 

 mesonotal furrows indicated oidy posteriorly and very faintly. Scu- 

 telluni high, transversely, convex. Metapleura sericeous. Tegula's 

 black. Wings hyaline, with pale i)ubescence. Legs brown, the tro- 

 chanters, tips of tibiie and tarsi pale. Abdomen a little longer than 

 the thorax, the petiole and the second segment at base striated. 



Habit vt. — District of Columbia. 



Types in National Museum. 



Described from 4 specimens, reared July 31, 1886, from a Cecidomyiid 

 gall iu the flower bud of alder. 



Polygnotus tumiduB, sp. nov. *' 



9. Length, 1""". Black, polished; head nearly 4 times as wide as 

 long antero-posteriorly, the vertex transversely sti' ted. Mandibles 

 brown. AntenuiTi 10 Jointed, brown-black; pedicel noi (juite as long as 

 the first and second funiclar Joints united; first funiclar Joint small ; sec- 

 ond and third nearly equal ; club .l-Jointcd, very wide; the second, third, 

 and fourth joints wider than long and at tips toward (me side a little 

 serrated, at base rounded, last Joint more slender and longer than the 

 preceding. Thorax ovoid, highly polished, the mesonotal furrows 

 only faintly indicated posteriorly. Scutellum high, convex, polished. 



