420 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. [1885. 



DESCRIPTIVE. 



Male. — Average length, 1.5™™; wing expanse, 2.6™™; greatest width of fore wing, 

 0.5mm. Scape somewhat broadened below, inserted near the middle of the face in a 

 deep groove, and reaches nearly to the ocelli. Flagellum long, flattened, hairy, each 

 joint except club with a whorl of long slender hairs at base. Funicle joints decreas- 

 ing in length slightly from 1 to 4, joint 1 rather more than twice as long as wide. 

 Head considerably shrunken after death. Head, prouotum, and mesonotum smooth 

 and shining; metanotum, pro, meso, and metapleura, and all coxa? above, finely 

 punctate. Submarginal vein of the fore wing with a single stout superior bristle 

 behind its middle ; marginal vein three times as long as stigmatal ; post-marginal 

 ■wanting. Median impressed line of mesosternum very distinct ; metanotal carina dis- 

 tinct, rather short. Abdomen narrow, compressed laterally, sub-acuminate. Gen- 

 eral color shiny black, with slight metallic reflections ; flagellum, brown ; all tro- 

 chanters, distal end of all femora, all tibai, and tarsi, honey yellow; wing veins, 

 brown, very distinct. 



Female. — Length (average), 2.1™™; wing expanse, 3.2™™; greatest width of fore 

 wing, 0.55™™. Scape slender, pedicel ovoid, ring joints very small; flagellum rather 

 short, but slightly compressed ; club ovate ; funicle joints subequal in size, joint 3 

 rather shorter than 1 and 2, its length exceeding its width but slightly. Abdomen 

 narrow, flattened dorso-ventrally, prolonged to an acute tip. 



Described from six males and seven females. 



Belongs in the first division of section 1 of Thomson's revision of the genus, and is 

 more nearly related to T. scaposus than to other species, chiefly on account of the dila- 

 tion of the S scape, but from this it is at once separated by the produced abdomen 

 of the $ . 



Platygaster herrickti Packard. 



[Plate XXI, fig, 6.] 



SYNONYMY. 



Platygaster ei-ror Fitch (?) Packard. Bufletin 4, U. S. Entomological Commission, 

 pp. a0,21; Washington, 1880. Third Report U. S. E. C.,pp. 219,220; Wash- 

 ington, 1883. 



Platygaster herrickii (?) Packard. Hid. 



In Bulletin 4 of the United States Entomological Commission Dr. Pack- 

 ard gave a description of a parasite received from Prof. A. J. Cook, 

 which had been bred from the coarctate larva of the Hessian Fly. 

 This parasite he identified doubtfully as the Platygaster error of Fitch, 

 stating that if later it should prove to be a different species it might be 

 called Platygaster herrickii. I adopt this latter name for the reason 

 that Fitch's description is so very indefinite that it will api)ly equally 

 well to almost any species of the genus, and that, inasmuch as Platy- 

 gaster error was bred by Fitch from the eggs of a Heteropterous insect, 

 it was iu all probability different from this Hessian Fly parasite. 



Concerning this parasite Professor Cook, in his lecture on the Hessian 

 Fly, says: 



" One of the parasites of the genus Platygaster is an egg parasite, as its young feed 

 on the eggs — mere specks as thej^ are — of the Hessian Fly. 



"It is black and looks not unlike a tiny gnat. The female feels for the eggs with 



