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True Flies — Part 6

Fourth vein not or only slightly curving toward the third.

Group ACALYPTERAE Macq.

40--Auxiliary vein distinct, separated from the first and terminating in the costa, the anal cell present.

Auxiliary vein absent, or confused with the first vein.

41--Anterior oral margin bearing a distinct bristle on either side.

Anterior oral margin never bearing such bristles, their places sometimes occupied by several short bristly hairs.

42--Costa of the wings bearing numerous spines, or the bristles of the front confined to the upper half.

Costa of the wings not beset with spines, front usually bristly from the vertex almost to the antennae.

43--Third joint of the antennae noticeably longer than broad.

Third joint broader than long, the last section of the fourth vein usually much longer than the preceding section.

44--Front edge of the wings not beset with spines (Sepsidae, in couplet 51).

Front edge of the wings beset with short spines, thorax convex, third joint of the antennae nearly circular.

45--Tibiae bearing an erect bristle on the outer side before the apex, anal and basal cells present.

Tibiae not furnished with such a bristle, anal cell present.

46--Body convex, the face and cheeks not unusually bristly.

Body greatly depressed, the face and cheeks unusually bristly.

47--Sixth vein of the wings prolonged to the wing-margin.

Sixth vein obliterated before reaching the wing-margin.

48--Legs usually short and robust, abdomen usually ovate and rather short, in the female furnished with a horny ovipositor.

Legs and body usually very elongate and slender, abdomen of female not furnished with a horny ovipositor, bristles of the front confined to the upper half.

49--Basal and anal cells large, the latter usually prolonged at its lower apical angle.

Basal and anal cells small, the latter not prolonged at its lower apical angle, bristles of the front confined to its upper half.

50--Auxiliary vein gradually curving to the costa toward its apex, bristles of the front confined to the upper half.

Auxiliary vein abruptly bent forward near its apex, bristles of the front extending from the vertex almost to its lower end.

51--Face in profile retreating on its lower part, palpi usually large, third and fourth veins usually strongly converging toward their apices.

Face perpendicular and somewhat projecting forward on its lower part, palpi minute, third and fourth veins parallel or diverging toward their apices.

52--Femora and usually the body short and robust.

Femora slender and elongated, body also usually elongated, anal cell present.

53--Fourth vein parallel with or diverging from the third vein.

Fourth vein usually curving toward the third at its apex (Micropezidae, in couplet 51).

54--Head nearly hemispherical, not prolonged laterally.

Head prolonged laterally, the eyes situated at the apices of the prolongations, front femora very robust.

55--Anterior oral margin bearing a distinct bristle on either side.

Anterior oral margin not bearing such bristles.

56--Anal cell usually wanting, the second basal cell usually confluent with the discal cell.

Anal cell distinct, second basal cell usually separated from the discal cell(Agromyzidae, in couplet 60).

57--Antennal arista frequently long-pectinate on the upper side, head usually much wider than high, face usually provided with bristles especially on each side, and the oral opening sometimes excessively large.

Antennal arista never long-pectinate, head not wider than high, face not bristly, and the oral opening never unusually large.

58--Arista of antennae bare, body short and robust.

Arista usually plumose; if bare the body is some what slender.

59--Hairs of the antennal arista long and few in number, second basal cell usually confluent with the discal cell.

Hairs of the arista short and numerous, sometimes wanting; second basal cell separated from the discal cell.

60--First joint of the posterior tarsi slender, longer than the second joint

First joint greatly dilated, shorter than the second.

Sub-order EPROBOSCIDEA Latr.

61--Head greatly depressed, projecting forward or downward, body usually depressed; living on mammals (exceptbats), birds, or honey bees.

Head rounded, projecting backward upside down over the thorax, body usually nearly cylindrical; living upon bats