ABT. 16 NORTH AMERICAN ICHNEUMON-FLIES CUSHMAN 49 



Derocentrus texanus (Ashmead) Cushman, Proc. Ent. Soc. Wash., vol. 21, 



1919, p. 114. 

 Derocentrus graeilipes (Cresson) Gttshman, Proc. Ent. Soc. Wash., vol. 21, 



1919, p. 114. 



In spite of the p;reat difference in color between the sexes there 

 seems to be no doubt that they belong to the same species. 



Discussion based on types of longicaudius, maeilentus, texanus (ap- 

 parently the same specimen as type of longicaudus) and the para- 

 typo of fexamis, a homotype (Gahan) of exdamans^ a homotype 

 (Cushman) of niacilentiLS, a specimen compared by Cushman with 

 the type of gracUrpes, and 20 other females and 23 other males. 



Female. — Length, 8-12 mm. 



Temples convexly receding; malar space nearly as long as basal 

 width of mandible; flagellum very slender and of uniform thiclmess, 

 first joint fully eight time as long as thick. Thorax twice as long as 

 deep, sparsely punctate dorsally and ventrally, more densely so 

 laterally; pronotum polished, practically unsculptured except a 

 foveolate groove along posterior margin; notauli foveolate; ^vo- 

 podeum opaque rugulose; nervellus broken not far below middle, 

 reclivous, upper abscissa perpendicular to cubitella. Abdomen sub- 

 polished, very faintlj^ coriaceous; first tergite polished. 



Body and legs nearly uniformly ferruginous, ventrally and about 

 the scutellum and postscutellum more or less stained with black; 

 antennae ferruginous at base, black beyond Avith a small, incomplete 

 annulus centering on flagullar joint 8; wings uniformly pale in- 

 fumate. 



Male. — Temples nearly as broad as eyes and more strongly con- 

 vex than in female; malar space barely two-thirds basal width of 

 mundible ; flagellum rather stout at base, tapering toward apex, first 

 joint hardly four times as long as thick. Thorax more coarsely 

 sculptured; lateral impression of pronotum strongly striated; ab- 

 domen linear. 



Head and thorax black with whitish markings as follows: Orbits, 

 except interruption at top of eye and usually in malar space; some- 

 times middle of face and clypeus; mandibles; anterior and humeral 

 margins of pronotum; spot in middle of mesoscutum; scutellum; 

 subalar tubercle; usually an elongate mark or two spots on lower 

 part of mesopleurum ; upper division of metapleurum and about the 

 dorsal half of lower division, and sides of apical face of propodeum 

 broadly ; antennae black, scape rarely reddish ; legs testaceous, coxae 

 usually more or less white, sometimes more or less black at base ; basal 

 joint of hind trochanter sometimes piceous; apex of tibia and first, 

 fourth, and fifth tarsal joints sometimes more or less blackish, joints 

 2 and 3 largely white; wings paler than in female; abdomen fer- 



