107 (106). Hind metatarsus longer than and not thicker than C, I(6). 108 (115). X, 5^1 absent, X, 5^2 present (_i.e._ only one X-vein on V, 5 and that placed beyond X, 4 (_plate_ V, 36). 109 (110). Legs long and thin; abdomen very long. _Part of_ MICROPEZIDÆ, XL (genus Micropeza) 110 (109). Legs short and strong; D oval or elliptical. 111 (112). A, III (6) absent; A, IV (5) round, or, if lengthened, then A in profile is triangular. CHLOROPIDÆ, LI 112 (111). A, III (6) present; A, IV (5) generally long or oval; A in profile never triangular. 113 (114). Head square; face strongly convex (_plate_ VII, 21); O, 6^1 absent. Not orange coloured species. EPHYDRIDÆ, XLIX 114 (113). Head round or semi-circular; face not arched (_plate_ VII, 19); O, 6^1 present, or, if absent, then the species orange coloured. _Part of_ DROSOPHILIDÆ, L. 115 (108). X, 5^1 present, or, if absent, then X, 5^2 also absent (_i.e._, either two X-veins or no X-veins on V, 5) (_plate_ V, 33, 38). 116 (117). Scutellum of the male extraordinarily long and squared off behind; costa thickened from the end of V, 1 to the wing tip. _Part of_ PHYCODROMIDÆ (genus Thyreophora) 117 (116). B, I (6) usually short, and somewhat triangular; costa normal. 118 (133). Mouth bristles present. 119 (122). Fronto-orbital bristles absent. 120 (121). Wings without a black spot near the tip. PIOPHILIDÆ, XLVII 121 (120). Wings with a black spot near the tip. _Part of_ SEPSIDÆ, XLVI 122 (119). Fronto-orbital bristles present. 123 (128). X, 5^2 before middle of wing (both X, 4 and X, 5^2 near the base and exceedingly near together) or no X-vein on V, 5. 124 (127). X, 5^2 immediately under X, 4 (or nearer the base), or X, 5^1 and X, 5^2 both absent (_plate_ V, 38). 125 (126). Arista bare or nearly so. _Part of_ PHYTOMYZIDÆ, LIV 126 (125). Arista with long hairs on one side. ASTIADÆ, LV 127 (124). X, 5^2 present and placed further from base than X, 4. _Part of_ AGROMYZIDÆ, LIII 128 (123). X, 5^2 at or beyond the middle; X, 4 and X, 5^2 neither very near to the wing base nor to one another. 129 (130). Arista bare; body short and broad. MILICHIDÆ, LII 130 (129). Arista plumose, combed, or pubescent, or, if bare, then the body always narrow and long. 131 (132). Arista thinly but long haired, plumose, or combed. _Part of_ DROSOPHILIDÆ, L 132 (131). Arista thickly and short haired, pubescent, or bare. GEOMYZIDÆ, XLVIII 133 (118). Mouth bristles absent. 134 (137). O, 5^1 and O, 6^1 large and very prominent. 135 (136). Antennæ moderately long or very long, male genitalia not prominent. _Part of_ PSILIDÆ, XXXIX