These are rare flies, small to minute, usually dark-colored, and generally found in grassy places. Most of the 13 N. American species occur in Canada and w. U.S.

LEAF MINER FLIES Family Agromyzidae

Identification: Small to very small flies, usually blackish or yellowish. Sc incomplete or fused with Ri. Costa broken near end of Ri. Anal cell present. Sternopleural bristles present. Postvertical bristles diverge. Oral vibrissae present. No preapical tibial bristles. 6 abdominal segments.

Leaf miner flies are common insects usually occurring on vegetation. Larvae are mostly leaf miners and generally make a narrow winding mine; some feed in stems and seeds.

ODINIID FLIES Family Odiniidae Not illus.

Identification: Similar to Agromyzidae, but with preapical tibial bristles and 5 abdominal segments.

Adults of this small group occur around rotting logs and sap flows but are uncommon. Larvae are scavengers.

SHORE FLIES Family Ephydridae

Identification: Most species blackish and relatively small; some very small. Sc incomplete. Costa broken near end of Ri and near humeral cross vein. Anal cell absent. Face usually somewhat bulging. Oral vibrissae absent. Postvertical bristles diverging (sometimes small and difficult to see).

Shore flies are common insects often occurring in large numbers along the shores of ponds and streams and along the seashore. Larvae are usually aquatic. Larvae of the seashore species live in brackish water and adults often cluster in large numbers on the surface of pools just above the high tidemark.

MILICHIID FLIES Family Milichiidae Identification: Very small flies, usually blackish. Sc incomplete. Costa broken near end of Ri and near humeral cross vein. Anal cell present. Postvertical bristles converging or parallel. Oral vibrissae weakly developed. At least 1 pair of fronto-orbital bristles bent inward.

Milichiids are fairly common in grassy areas. Larvae are scavengers.

POMACE FLIES Family Drosophilidae See also p. 283

Identification: Usually yellowish or brownish, 3-4 mm. Sc incomplete. Costa broken near end of Ri and near humeral cross vein; not spiny. Anal cell present. Postvertical bristles converge. Oral vibrissae well developed. Arista plumose. Sternopleural bristle present; no mesopleural bristles.

Pomace flies are very common, and are usually found near

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