Key to identincation of the Nearctic species of the Anthomyza macra group

1 Male. ........................................................................................................................... 2

– Female. ........................................................................................................................ 4

2(1) Gonostylus suboblong in widest extension outline (Fig. 231); apex of nlum bluntly truncate (Fig. 229); scutellum often medially pale brown to yellow. ............................ ..................................................................................................... A. oblonga sp. nov.

– Gonostylus distally strongly widened in widest extension outline (Figs 214, 242); apex of nlum lanceolate (Figs 211, 246); scutellum usually brown (sometimes medially pale brown in A. tenuis). ..................................................................................................... 3

3(2) Epandrium very large and broad (largest dorsal width of epandrium more than 1.1 times as long as longest eye diameter), with anal nssure small and low (Fig. 207). Gonostylus laterally as large as epandrium (Fig. 208), distally more widened and with small acutely projecting posteroventral corner (Figs 207, 214). Posterior process of pregonite with more (4–5) setae (Fig. 209). Saccus with numerous spines (Fig. 212). Humeral callus usually yellow. ................................................ A. tenuis (Loew, 1863)

– Epandrium smaller, less broad (largest dorsal width of epandrium less than 0.9 times as long as longest eye diameter), with anal nssure larger and higher (Fig. 239). Gonostylus laterally smaller than epandrium (Fig. 248), distally less widened and with more robust, less pointed posteroventral corner (Figs 241–243). Posterior process of pregonite with only 2 setae (Fig. 244). Saccus with only a few spines (Fig. 247). Humeral callus light brown to brown. ......................................................... A. silvatica sp. nov.

4(1) Preabdominal terga (T2–T5) entirely brown. Pleural part of thorax with dorsal longitudinal brown band wider, usually covering dorsal one-third or more of mesopleuron; humeral callus light brown to brown; scutellum always brown. T7 dorsomedially shortened (Fig. 249), with anterior emargination; T8 transverse and pale (Fig. 249); S8 short, usually with a few setae (Fig. 253). .................................... A. silvatica sp. nov.

– T2–T5 dorsally largely yellow or at least distinctly paler brown than laterally. Pleural part of thorax either entirely yellow or only narrowly brown at dorsal margin of mesopleuron; humeral callus yellow or brownish; scutellum may be medially light brown in A. tenuis to distinctly yellow in A. oblonga . T7 dorsomedially longer, shallowly emarginate (Figs 216, 234); T8 as long as wide or slightly transverse, narrower posteriorly and darker (Figs 216, 234); S8 elongate, with more setae (Figs 217, 238). ............... 5

5(4) Large dorsal yellow parts of T2–T5 usually contrasting with brown lateral parts (Fig. 232). T7 usually shorter and wider and with sides convex to straight (Fig. 234). Annular sclerite strongly bent in pronle (Fig. 233). Spermathecae with basal part markedly narrower, more distinct from wider terminal part which is more densely, nnely ringed (Figs 235, 237). ............................................................................. A. oblonga sp. nov.

– Dorsal yellow to pale brown parts of T2–T5 continuously transitioning to brown lateral parts. T7 usually longer and narrower and with sides concave (Fig. 216). Annular sclerite slightly bent in pronle (Fig. 218). Spermathecae with basal part markedly broader, less distinct from wider terminal part which is less densely, coarsely ringed (Figs 215, 221). ........................................................................ A. tenuis (Loew, 1863)