4 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.61. 



minute, usually indistinct, tarsal claws; the smooth eyes; the narrow 

 radial cell, the third abscissa of radius being parallel with the outer 

 margin of stigma ; the subquadrate second cubital cell ; and the very 

 short thickened metacarpus. 



Bengtsson, in the article cited above, gives a concise summary of the 

 published information regarding the biology and habits of members 

 of this group. It appears to have been conclusively shown that the 

 known species pass the larval period as internal parasites of ants. 

 This unusual habit itself will at once set them apart from the Micro- 

 gasterlnae, which are evidently exclusively parasitic on lepidopterous 

 larvae. 



KEY OF THE GENERA OF NEOXEURINAE. 



Radial cell complete, the radius distinct to the wing-margin; antennae 16- 

 segmented, and but little shorter than body Neoneurus Haliday. 



Radial cell incomplete, the last abscissa of radius mostly obsolete; antennae 

 13-segmented in tlie female, 14 in the male, and very short; porrect, shorter 

 than head and thorax united Elasmosoma Ruthe. 



Genus NEONEURUS Haliday. 



Neoneurus Haliday, Ent. Mag., vol. 5, 1838, p. 213.— Snellen van Vollen- 

 HOVEN, Schetsen, vol. 2, 1869, pi. 6.— Marshaijl, in Andr6, Hym. Eur. et 

 Alg., vol. 5bis, 1897, p. 197, pi. 10, fig. 3.— Ashmead, Proc. U. S. Nat. Mus., 

 vol. 23, 1900, p. 130.— Szepligeti, Gen. Ins., fasc. 22. 1904, p. 318.— 

 Bengtsson, Lund. Univ. Arsskr. N. F. Avd. 2, vol. 14, 1918, pp. 1-^47. 

 Genotype. — Neoneurus /toMd'ou Marshall (^Monobasic). 



Head large, transverse, as broad as thorax ; maxillary palpi 2-seg- 

 mented, labial 1-segmented ; eyes large but not prominent, bare, con- 

 verging in female ; occiput convex ; antennae of both sexes slender, as 

 long as the body nearly, 16-segmented ; parapsidal grooves weakly 

 indicated; scutellum separated from mesoscutum by a transverse 

 sulcus ; anterior wing with a very short complete radial cell, which is 

 divided by a more or less distinct cross-vein ; three cubital cells, the 

 second small, subquadrate; recurrent vein indistinct or incomplete, 

 the five-sided discoidal cell open outwardly ; legs slender ; the poste- 

 rior trochanters small, almost indistinct; spurs of posterior tibiae 

 half as long as the metatarsus; tarsal claws minute; abdomen sessile, 

 flat and finely shagreened above, keeled below. 



Morley^ was beyond all doubt mistaken in identifying Neoneurus 

 halidali Marshall with Elasmosoma herolinense Ruthe. Marshall's 

 characterization and figure show conclusively that the genotype of 

 Neoneums is distinct from that of Elasmosoma. 



No representative of this interesting genus has yet been discovered 

 in North America ; but it is not at all unlikely that further collecting 

 in the immediate vicinity of ants' nests will produce it. 



8 Ent. Mas., vol. 50, 1914, p. 16. 



