Order—Diptera

1 (141). Insects with the head distinct from the thorax, with one pair of wings, one pair of halteres, 5-jointed tarsi, proboscis not spirally coiled; with a well defined pupal stage intermediate between the larval stage and the perfect insect.

1-1/2 (52-1/2). Frontal lunule absent.

Sub-order I. ORTHORRHAPHA (comprising 25 families); flies with "mummy-pupÆ," see plate VI, figs. 38 and 39.

2 (25). AntennÆ many-jointed (plate II).

NEMATOCERA (thread-horns)—

3 (4). Vein endings round the margin (plate IV, figs. 1, 2, 3) not more than 6.

4 (3). Vein endings more than 6.

5 (20). Thorax (plate VI, 31) without B, I, 8 conspicuous.

6 (15). Costa ending at apex of wing (plate IV, 4-11).

7 (12). Ocelli as in plate I, or as in plates VI, I and II, 4.

8 (9). Discal cell (O, 4b or O, 5²) present (plate IV, 16).

9 (8). Discal cell absent (plate IV, 4-7).

10 (11). AntennÆ long (plate II, 3-6); or, if short, coxÆ elongated.

11 (10). AntennÆ as in plate II, 7 and 8; coxÆ not elongated.

12 (7). Ocelli absent.

13 (14). AntennÆ (plate II, 9) shorter than B; wings (plate IV, 9) broad.

14 (13). AntennÆ (plate II, 10, 11) longer; wings narrow (plate IV 9-11).

15 (6). Costa (plate IV, 12-14) around hind margin.

16 (17). Wings held roof-like, hairy; X only at base (plate IV, 12).

17 (16). Wings flat over D; X on middle of wing.

18 (19). Veins hairy (plate IV, 13).

19 (18). Veins bare.

19a (19b). AntennÆ long; V, 4 and V, 2 forked; X, 4 (plate IV, 14) ending in V, 2.

19b (19a). AntennÆ very short but 11-jointed; no veins forked.

20 (5). Thorax (plate VI, 32) with a strong cross seam.

21 (22). V, 6 absent (plate IV, 15).

22 (21). V, 6 present.

23 (24). V, 1a ending in costa and (plate IV, 17-22) united to V, 1b by X, 1b; last joint of palpi (plate VI, 4) never whip-like.

24 (23). V, 1a ending in V, 1b; and, except for X, 1a at its base, not united by X (plate IV, 23-26); palpi (plate VI, 5).

25 (2). AntennÆ short, 3-jointed (plate III); 3rd joint sometimes ringed.

BRACHYCERA (short-horns)—

26 (140). Wing veining normal; X-veins present.

27 (32). Third antennal joint ringed; A, IV, 6, if present (plate III, 1-9) apical.

28 (29). Costa ending at apex of wing (plate V, 1).

29 (28). Costa around the hind margin (plate V, 2).

30 (31). SquamÆ very large.

31 (30). SquamÆ very small.

32 (27). Third joint of antennÆ (plate III, 10-55) not ringed.

33 (55). Arista terminal or wanting (plate III, 10-26, 28-32, 35-40, 48)

34 (46). V, 3 forked (plate V, 3-10, 13).

35 (45). O, 6¹ long, extending (or nearly) to hind margin, or entirely wanting (plate V, 3-9, 13).

36 (39). C, I, (II) much enlarged, appearance of 3 foot-pads (plate VI, 9)

37 (38). SquamÆ small, not covering C, III; O, 6¹ long and distinct (plate V, 3); long bodied flies, head of normal proportions.

38 (37). SquamÆ very large, hiding the halteres; O, 6¹ absent (plate V, 13); short round-bodied flies with very small heads.

39 (36). Empodium small, only 2 foot-pads apparent (plate VI, 10, 11).

40 (41). Vertex hollowed out between the eyes (plate VI, 28).

41 (40). Vertex flat or raised, eyes not protruding.

42 (43) (44). V, 4 ending in 3 branches (plate V, 6, 7) between V, 3 and V, 5.

43 (42) (44). V, 4 ending in 4 branches (plate V, 8) between V, 3 and V, 5.

44 (42) (43). V, 4 ending in 2 branches (plate V, 9); antennÆ (plate III, 23) without A, IV, 6.

45 (35). O, 6¹ short (plate V, 10) not nearly reaching hind margin.

46 (34). V, 3 not forked (plate V, 11-12, 14-17).

47 (52). AlulÆ absent or rudimentary.

48 (51). Apex of the wing rounded.

49 (50). X, 4 placed generally beyond X, 5¹, at most only a little before it; V, 5 with 2 X-veins bounding a discal cell (plate V, 11); or, if only one, then X, 5 is placed before, or, at most (plate V, 12) only a little beyond X, 4.

50 (49). X, 4 placed very near the base of the wing; V, 5 with only one X-vein placed far beyond X, 4; no discal cell (plate V, 14, 15).

51 (48). Apex of the wing (plate V, 16) pointed.

52 (47). AlulÆ present.

52-1/2 (1-1/2). Frontal lunule (plate VII, 5) present.

Sub-order II. CYCLORRHAPHA (families XXVI—LX); flies which escape from a puparium, formed of the indurated larval skin, through a circular orifice made by pushing off its head end (plate VI, 37).

PROBOSCIDEA—

53 (54). AntennÆ (plate III, 39, 40) with a long seta or bristle.

54 (53). AntennÆ (plate III, 48) with a short seta or spine.

55 (33). Arista dorsal (plate III, 27, 33, 34, 41-47, 49-55).

56 (61). O, 6¹ long (plate V, 18-21-1/2) extending nearly to hind margin: D without strong bristles (macrochÆtÆ).

57 (60). Proboscis of moderate length (plate VI, 12-16) generally retracted.

58 (59). Vena spuria (plate V, 18) absent; A, II very large; O, 4² open.

59 (58). Vena spuria present (plate V, 19-21); O, 4². closed; A, II moderate.

60 (57). Proboscis projecting far in front, very thin and long, often double-kneed (plate VI, 27); no vena spuria (plate V, 21-1/2).

61 (56). O, 6¹ short, not nearly reaching margin, or absent (plate V, 12, 22-39) abdomen often with strong bristles.

62 (63). Proboscis and palpi atrophied.

63 (62). A, VIII, 3 and 4 distinctly present.

64 (67). X, 5¹ absent, X 5² present, i.e., only one X-vein on V, 5 and that beyond X, 4.

65 (66). X, 4 very near base of wing (plate V, 14, 15); X, 5 far beyond X, 4.

66 (65). X, 4 more towards middle of wing (plate V, 12, 36, 37) nearer X, 5.

66a (66b). Proboscis directed straight downwards.

66b (66a). A, VIII, 3 retracted [ordinary Muscid type] pass on to 108 of this table.

67 (64). X, 5¹ present, that is, a X-vein on V, 5 before, or under X, 4; or no X-veins on V, 5.

68 (69). No X-veins on V, 5.

Part of PhytomyzidÆ, LIV

69 (68). At least X, 5¹ present, generally also X, 5².

70 (75). SquamÆ distinctly present though sometimes small.

MUSCIDÆ CALYPTERÆ—

71 (74). V, 4 angled or bent towards V, 3 (plate V, 24-29).

72 (73). D with E (macrochÆtÆ and hairs) on middle segments; otherwise A, IV, 6 is bare or bare on the tip-half (plate III, 49-50).

73 (72). D without macrochÆtÆ though often with rather strong hairs; A, IV, 6 fully plumed or combed (plate III, 51).

74 (71). V, 4 going straight or nearly straight to margin (plate V, 30).

75 (70). SquamÆ absent or rudimentary.

MUSCIDÆ ACALYPTERÆ—

76 (105). V, 1a distinctly present, nearly as thick as V, 1b, which generally ends in the fore margin at or beyond the middle of the wing (plate V, 31, 32, 34).

77 (84). VibrissÆ present (plate VIII, 2) together with more or less hair.

78 (79). V, 4⁴ four or five times as long as V, 4³ (i.e., X, 5² nearer X⁴ than to wing margin).

79 (78). V, 4⁴ about equal to V, 4³, or only a little longer.

80 (81). Costa with spines in addition to the ciliation (plate VII, 14).

81 (80). Costa without a row of spines, only ciliated.

82 (83). A, III (5) present, or, if absent, then body never shining black.

83 (82). Fronto-orbital bristles absent; body always shining black.

84 (77). VibrissÆ absent; mouth with short hairs or bare (plate VII, 1, 3, 4); or, if the hairs are strong, all of same length and strength.

85 (88). A, IV very long and horizontal; A, IV (4) as long or longer than A, IV (5) of which the upper edge is concave (plates III, 54; VII, 1).

86 (87). Profile not triangular; face perpendicular or slightly retreating.

87 (86). Profile triangular; A, V retreating (plate VII, 1) almost horizontally.

88 (85). AntennÆ not long, or, if long, drooping; A, IV (4) shorter than A, IV (5) of which the upper edge is straight or convex.

89 (90). Brown or black shore flies with flat horny thorax and with strong mouth hairs.

90 (89). Otherwise than 89.

91 (94). O, 5¹ and O, 6¹ very small and indistinct.

92 (93). Only one fronto-orbital bristle on each side; tibiÆ all without the prÆ-apical bristle.

93 (92). A, III (5) on each side; the prÆ-apical E on some of the C, I (4).

94 (91). O, 5¹ and O, 6¹ fairly large and quite distinct.

95 (96). Hind tibiÆ with a prÆ-apical bristle.

96 (95). Hind tibiÆ without the prÆ-apical bristle.

97 (98). A, III (6) present and close to A, II; V, 1a sharply bent up at its end (plate V, 34). Wings usually spotted; ovipositor protruding.

98 (97). Lower fronto-orbital bristles absent; V, 1a gently bent up.

99 (104). Legs long; abdomen narrow and long, contracted at base.

100 (103). V, 4 straight or nearly so. Shining black species.

101 (102). V, 6 reaching to the wing margin; abdomen narrow, more than twice as long as the thorax.

102 (101). V, 6 not nearly reaching margin; D rather broad.

103 (100). V, 4 much bent towards V, 3. Brown species.

104 (99). Legs normal; D comparatively short and broad, never contracted at base.

105 (76). V, 1a absent or rudimentary, much thinner than V, 1b, which latter ends at or before the middle of the fore margin.

106 (107). Hind C, I (5) thickened and shorter than the next joint.

107 (106). Hind metatarsus longer than and not thicker than C, I(6).

108 (115). X, 5¹ absent, X, 5² 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.

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.

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, 6¹ absent. Not orange coloured species.

114 (113). Head round or semi-circular; face not arched (plate VII, 19); O, 6¹ present, or, if absent, then the species orange coloured.

115 (108). X, 5¹ present, or, if absent, then X, 5² 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.

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.

121 (120). Wings with a black spot near the tip.

122 (119). Fronto-orbital bristles present.

123 (128). X, 5² before middle of wing (both X, 4 and X, 5² near the base and exceedingly near together) or no X-vein on V, 5.

124 (127). X, 5² immediately under X, 4 (or nearer the base), or X, 5¹ and X, 5² both absent (plate V, 38).

125 (126). Arista bare or nearly so.

126 (125). Arista with long hairs on one side.

127 (124). X, 5² present and placed further from base than X, 4.

128 (123). X, 5² at or beyond the middle; X, 4 and X, 5² neither very near to the wing base nor to one another.

129 (130). Arista bare; body short and broad.

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.

132 (131). Arista thickly and short haired, pubescent, or bare.

133 (118). Mouth bristles absent.

134 (137). O, 5¹ and O, 6¹ large and very prominent.

135 (136). AntennÆ moderately long or very long, male genitalia not prominent.

136 (135). AntennÆ short; male genitalia prominent, and club-shaped.

137 (134). O, 5¹ and O, 6¹ small and not very prominent.

138 (139). Light grey or silvery species.

139 (138). Orange or brownish-red species.

140 (26). Wings with two short very thick veins (in fore-basal region) whence spring a few very fine unbranched veins. X-veins absent (plate V, 35).

141 (1) (52-3/4). Body of a horny or leathery nature; head sunk into a hollow in the thorax (plate VI, 35). No proper proboscis or palpi; claws very large (plate VI, 36). Perfect insect parasitic.

EPROBOSCIDEA—

142 (145). Head fairly large; wings sometimes shed or absent.

143 (144). Eyes, ocelli, scutellum, halteres, and wings all absent; last tarsal joint combed with bristles.

144 (143). Eyes and scutellum present; last tarsal joint with well developed claws.

145 (142). Head small, when at rest thrown back upon the dorsum; always wingless.