4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 79 



The tribe Decatomini - differs from it8 nearest relatives, the Eury- 

 tomini, and other tribes of the family in possessing a distinct stigma 

 (pi. 1, figs 1 to 13, et al.) near the middle of the anterior margin 

 of the front wings. Ashmead ^ recognized two genera in this tribe, 

 splitting his genus Eudecatoma from DecatOTim' Spinola on the ab- 

 sence of a submarginal color band on the front wings. No adequate 

 structural differences, however, have been found that supplement 

 this somewhat variable character in the color band to justify this 

 division of the old genus Decatortia. To Masi,"* also, Eudecatcytna 

 Ashmead does not seem sufficiently different to regard it as a separate 

 genus. These genera have therefore been recombined in this study, 

 and the tribe Decatomini, as known in America north of Mexico, 

 includes the single genus Decatomia Spinola. 



Genus DECATOMA Spinoia 



Deodtoma Spiaola, Classification des diplolepaires, Ann. Mus. d'Hist. Nat., 

 vol. 17, p. 151, 1811.— Walsh, x\.nier. Ent. and Bot, vol. 2, no. 10, p. 300, 

 1870.^ — Ashmead, Trans. Amer. Ent. Soc, vol. 9, p. xxxi, 1881. — Provan- 

 OHEK, Petite fauna entomologique dn Canada et particulierement de la 

 Province de Quebec, vol. 2, Hymenoptera, pp. 568-569, 1883. — Howabu, 

 U. S. Dept. Agr., Div. Ent. Bull. 5, pp. 38-39, 1885.— Ashmead. Ent. Amer- 

 icana, vol. 4, no. 3, pp. 42-43, 1888, new genus Eudecatoma. — Ashmead, 

 Trans. Amer. Ent. Soc, vol. 21, p. 319, 1894 {Diplolepis adonidum Rossi as 

 the genotype). — Brues, Bull. Mus. Comp. Zool. 54, p. 25, 1910. — Masi. 

 Nov. Zool., vol. 24, p. 138, 1917, Eudecatoma Ashmead synonymous with 

 Deoatoma Spinola.— Gahan and Faoan, U. S. Nat. Mus. Bull. 124, 1923, list 

 of type species, Deoatoma, p. 59, and Eudecatoma, p. 42. Only the chief 

 papers on the genus are listed. 



Maximilian Spinola described Deoatoma as genus No. 19 with a 

 series of other genera, as follows, the first phrase occurring in the 

 key : "Antennis de dix articles, inserees au milieu du front. * * * 

 N. 19. G. Decatonui. Abdomen petiole, comprime lateralement, 

 * * * Mihi. Ex. Chalcis adonld'wni Rossi, Diylolepis Sphegnum, 

 stigvia Fabr. etc. Decatonna splendid>a^ Ttietdlica. ruflpes^ albitat'sis 

 mihi. Medites, etc." 



Fe^rmle. — Length 1.5 to 4 mm., moderately robust in form, or no 

 more than four times as long as maximum width (head and meso- 

 thorax), varying from almost black through brov/n to nearly com- 

 pletely yellow, the intermediate colors being combinations of black, 

 brown, red, and yellow, black species with cephalo-lateral angle of 

 pronotum yellow, yellow species with at least a part of hind legs 

 partly fuscous to black; submarginal band lacking, or faint j)ale 

 brown to deep brown, a faint secondary band broadly V-shaped and 

 on ridge between band and base of wings sometimes present. 



-Ashmead, Classification of the chalcid flies. ]Vfera. Carncijie M\is., vol. 1, no. 4, 1904. 

 s Ent. Americana, vol. 4, no. :j, pi>. 42, 43, 1888. 

 ♦Nov. Zool., vol. 24, p. 138, 1917. 



