1	Wing with vein CuA1 arising from apex of cell bm; connected to discal cell by cross-vein m-cu; three medial veins present; male epandrium not medially divided	2
–	Wing with vein CuA1 integrated into at least part of posterior margin of discal cell; one or two (rarely three) medial veins present; male epandrium medially divided	3
2	Antennal style elongate and filamentous	Apsilocephalidae
–	Antennal style very short, often barely evident	Therevidae
3	Antennal flagellum comprised of bulbous base fused with a terminal filamentous style; vein CuA2 separate from A1 to wing margin	Evocoidae
–	Antennal flagellum shape variable, but never with an elongate terminal filament; vein CuA2 joining to A1, petiolate to wing margin	Scenopinidae: 4
4	Wing with two veins originating posteriorly from discal cell (M1 and CuA1); male genitalia rotated 180°	Scenopininae: 11
–	Wing with three (or rarely four) veins originating posteriorly from discal cell (M1, M2, M3 and CuA1); male genitalia not rotated	5
5	Costal vein extending around wing; sensory area on tergite 2 made up of two hemispherical regions of short setae; male genitalia with aedeagus and gonocoxal apodemes short (Nearctic)	Caenotinae: Caenotus Cole, 1923
–	Costal vein ending at vein R5; male genitalia with aedeagus and gonocoxal apodemes greatly elongate	Proratinae: 6
6	Abdominal tergite 2 setal patch absent; antennal flagellum abruptly turbinate with a tuft of apical setae; thickening of costal margin ending at or just beyond R4; abdomen largely white with brown terminalia (Nearctic)	Caenotoides Hall, 1972
–	Abdominal tergite 2 setal patch present; antennal flagellum cylindrical or tapered, without tuft of apical setae; thickening of costal margin ending at or just beyond R5; abdomen typically uniform black, brown or pale yellow	7
7	Mouthparts elongate; antennal flagellum cylindrical; elongate setae along posterior margin of female abdominal tergite 8; male wing with M1 much shorter than M2; male gonocoxites with medial spine projecting posteriorly; gonocoxal apodemes and aedeagus barely projecting anteriorly from gonocoxites (Neotropical: Argentina)	Jackhallia Nagatomi & Liu, 1994
–	Mouthparts length variable; antennal flagellum usually tapered, although sometimes cylindrical; setae along posterior margin of female abdominal tergite 8 short; male wing with M1 longer than or equal length of M2; male gonocoxites without medial spine; gonocoxal apodemes and aedeagus project anteriorly well beyond gonocoxites, sometimes greatly elongated	8
8	Abdominal tergite 2 setal patch rounded with very slight medial separation into two hemispheres; female tergite 8 with erect, elongate setae arranged in ring-like pattern; male aedeagus folded dorsally onto itself so that ejaculatory apodeme is projecting posteriorly (Afrotropical: Namibia)	Cyrtosathe Winterton & Metz, 2005
–	Abdominal tergite 2 setal patch as a single rounded or elongate patch; female tergite 8 without erect, elongate setae; male aedeagus extending anteriorly and not folded on itself	9
9	Antennal flagellum gradually narrowed apically, with thick apical style that is wider than apex of preceding segment; anterior margin of female eye not emarginate (Nearctic)	Acaenotus Nagatomi & Yanagida, 1994
–	Antennal flagellum only slightly tapered, with narrow apical, or more commonly subapical, style that is not wider than apex; anterior margin of female eye often triangularly emarginate just dorsal to base of antennae	10
10	Antennal flagellum with single segment (excluding apical style) (Palaearctic)	Alloxytropus Bezzi, 1925
–	Antennal flagellum two segmented (excluding apical style), apical segment is minute and similar shaped to style in some species (e.g. Prorates frommeri Hall, 1972) (Nearctic)	Prorates Melander, 1906
11	Wing vein M1 separate from vein R5 to wing margin (cell r5 open)	12
–	Wing vein M1 fused to vein R5 before wing margin (petiolate closed cell r5)	16
12	Wing vein M1 incomplete or terminating before wing margin	13
–	Wing vein M1 complete to wing margin	14
13	Male epandrium as two relatively short lobes; female with reduced spines on acanthophorite; female sternite 8 longer than tergite 8 (Australasian)	Riekiella Paramonov, 1955 (part)
–	Male epandrium as four elongate lobes; female acanthophorite spines elongate, slender; female tergite 8 and sternite 8 subequal (Australasian)	Paramonova Kelsey, 1970 (part)
14	Vein CuA1 terminating just beyond cell d; female sternite 8 with comb-like band of elongate setae (Afrotropical, Oriental)	Seguyia Kelsey, 1980
–	Vein CuA1 reaching or terminating just prior to posterior wing margin; female sternite 8 without distinct comb-like band of elongate setae	15
15	Head length generally longer than height (sometimes subequal); body elongate; abdomen elongate and cylindrical; reared from wood-boring beetle galleries (Afrotropical, Palaearctic, Oriental)	Prepseudatrichia Kelsey, 1969
–	Head length generally shorter than height; body relatively short; abdomen wide; reared from various habitats but not known from wood-boring beetle galleries (cosmopolitan)	Scenopinus Latreille , 1802
16	Mouthparts atrophied (Nearctic)	BelostaHardy, 1944
–	Mouthparts well developed	17
17	Head generally longer than high; body glossy black with verrucous surface microsculpturing, without extensive setal pile; abdomen greatly elongate and cylindrical along entire length; reared from wood-boring beetle galleries or vertebrate nests	18
–	Head generally shorter than high; body glossy black or frequently with extensive pubescence, surface microsculpturing absent, often with extensive setal pile; abdomen short and flat, sometimes greatly elongate and tapered in female, never cylindrical along entire length; not known from wood-boring beetle galleries	19
18	Male epandrium approximately as long as high (lateral view); posterior margin of sternite 6 unmodified, without processes; male gonostyli with comb-like band of elongate setae; female cerci without tuft of strong spines; apex of cell r5 blunt (Nearctic, Neotropical)	Pseudatrichia Osten Sacken, 1877
–	Male epandrium distinctly shorter than high, band like (lateral view); truncated process along posterior margin of sternite 6; male gonostyli without elongate setae; female cerci with tuft of strong, ventrally directed spines; apex of cell r5acute (Australasian)	Neopseudatrichia Kelsey, 1969
19	Relatively robust bodied flies with broad, flat abdomen in both sexes (frequently large sized); sexes approximately equal sized	20
–	Relatively delicate flies with narrow tapered abdomen (usually with relatively small body size), particularly in female; abdomen much longer in female, displaying distinct sexual size dimorphism	22
20	M1 and composite R5+M1 vein abruptly bent anteriorly to join wing margin subapically along costa (Palaearctic)	Kelseyana nom. n.(= Caenoneura Kröber, 1923)
–	M1 and composite R5+M1 vein not bent anteriorly (Fig. 1A), joining margin at wing apex	21
21	Antennae greatly elongate and cylindrical; flagellum broadly rounded to truncate apically but not notched, style subterminal (Figs 1B-C); mouthparts greatly elongate; male distiphallus greatly elongate and coiled (Figs 4A-D); body reminiscent of bee fly (Bombyliidae) (Palaearctic: Iran)	Iranotrichia gen. n.
–	Antennae not elongate; flagellum ovate to quadrangular, notched apically with style terminal in notch; mouthparts rarely elongate; male distiphallus short and straight, rarely protruding beyond genitalic capsule; body not resembling bee fly	Metatrichia Coquillett, 1900 (Cosmopolitan) and Pseudomphrale Kröber, 1913 (Palaearctic)
22	Glossy black flies without pubescence; antennal flagellum pointed, not notched; female cerci with tuft of strong ventrally projecting setae (Palaearctic)	Stenomphrale Kröber, 1937
–	Body variously coloured with dense pubescence (rarely glossy black); antennal flagellum broad, notched apically; female cerci without tuft of strong setae	23
23	Wing with vein R4 branching from R5 along the basal half of cell r5; female acanthophorite spines well developed	24
–	Wing with vein R4 branching from R5 at halfway or along distal half of cell r5; female acanthophorite spines present, or reduced in size or shape, sometimes absent	25
24	Male distiphallus short and straight; male subepandrial sclerite not modified; female sternite 8 straight or slightly emarginate apically (Neotropical)	Heteromphrale Kröber, 1937
–	Male distiphallus relatively long and thread-like, highly reflexed basally so that basiphallus and ejaculatory apodeme are projecting dorsally or posteriorly; subepandrial sclerite with anterior projecting, blade-like extensions serving as aedeagal guides; female sternite 8 with rounded posterolateral lobes (Nearctic, Neotropical)	Brevitrichia Hardy, 1944
25	Female acanthophorite spines well developed (Afrotropical)	Propebrevitrichia Kelsey, 1969
–	Female acanthophorite spines absent, or greatly reduced in length or thickness (Australasian, Neotropical)	26
26	Female sternite 8 apically trilobate; male epandrium unmodified, without posterior or medial processes (Neotropical)	Irwiniana Kelsey, 1971
–	Female sternite 8 apically rounded or bilobate; male epandrium typically with multiple lobes and posterior or medial processes (Australasian)	27
27	Male epandrium with flange-like lobes internally	Paratrichia Kelsey, 1969
–	Male epandrium without flange-like lobes internally	28
28	Male epandrium as two relatively short lobes; female sternite 8 longer than tergite 8, apically pointed	Riekiella Paramonov, 1955 (part)
–	Male epandrium as four elongate lobes; female sternite 8 length subequal to tergite 8	Paramonova Kelsey, 1970 (part)