Key to the males of Efferia Coquillett from Puerto Rico and the Lesser Antilles

1 Palpi mostly pale setose, black setae usually sparse, at most apical 1/4–1/3 black setose........................................... 2

- Palpi mostly black setose, at least apical 1/2 black setose............................................................................................ 3

2 Palpi with several black setae on apical 1/4–1/3; pleuron mostly black setose dorsally; costal margin slightly to moderately dilated; abdominal tergites 6–7 white tomentose; sternites 7–8 often with long yellowish setae apically, extending beyond base of terminalia; apical margin of sternite 8 produced medially; gonocoxa entirely black setose, terminalia as in Figs. 97–100 ................................................................................................................ forbesi (Curran)

- Palpi pale setose, usually only 1–3 black setae apically; pleuron mostly pale setose dorsally, anepisternum with sparse black setae dorsally and posteriorly; costal margin not dilated; abdominal tergites 6–7 entirely and 5 apically white tomentose; sternites 7–8 without unusually long yellowish setae apically; apical margin of sternite 8 straight, not produced medially; gonocoxa black setose usually bordered by sparse pale setae basally, terminalia as in Figs. 116–119 ......................................................................................................................................... portoricensis (Hine)

3 Face with mostly or entirely black vestiture; epandrium short and wide, 2–2.5 times as long as wide, truncate dorsally; sternite 8 produced with apical setae usually dense, concealing gonocoxa basally; gonocoxal setae sparse posteriorly (Figs. 110–113)......................................................................................................... nigrimystacea (Macquart)

- Face with mixed black and pale vestiture medially or dorsally, pale vestiture laterally and ventrally; epandrium lon-

ger and narrower, 3 times as long as wide, apex not truncate dorsally; sternite 8 not strongly produced and without dense apical setae, setae never concealing gonocoxa basally; gonocoxal setae dense posteriorly (Figs. 103, 122) ... 4

4 Face, frons, and pro- and mesothoracic femora mostly or entirely golden yellow setose; postocular bristles yellow; scutum and basal 4 abdominal segments golden brownish-yellow tomentose; wing only slightly dilated; segments 5–7 white tomentose; epandrium with 2 spike-like processes dorsally; gonostylus wide apically; terminalia as in Figs. 103–106 .................................................................................................................................... montensis sp. nov.

- Face, frons and pro- and mesothoracic femora mostly or entirely white setose; postocular bristles black; scutum and basal 4 abdominal segments yellowish-gray tomentose; usually only segments 6–7 entirely and part of tergite 5 white tomentose, rarely 5–7 white tomentose; epandrium simple dorsally, spike-like processes absent; gonostylus narrow, blade-like apically; terminalia as in Figs. 122–125 .............................................................. stylata (Fabricius)