usually found on flowers or vegetation. Most species have attractively patterned wings; the wings may be banded or spotted, and the spotting sometimes forms intricate patterns. Some species move their wings slowly up and down while resting. Larvae are plant feeders, and a few are pests of fruits. Larva of Rhagoletis pomonella (Walsh) tunnels in the fruit of apple, and is called an Apple Maggot (PI. 14). The Mediterranean Fruit Fly, Ceratitis capitata (Wiedemann), is a serious pest of citrus.

Species of Eurosta form round, thick-walled stem galls on golden-rod. Many species breed in the flower heads of Compositae.

RUST FLIES Family Psilidae

Identification: Small to medium-sized, usually slender and brownish, with relatively long antennae. Species with a longitudinal suture on 2nd antennal segment have 3rd antennal segment very long, longer than arista. Species without this suture on antennae have Sc incomplete, costa broken near end of Ri, no sternopleural bristles, and no oral vibrissae.

Rust flies are fairly common insects. Larvae are plant feeders, and some species are pests of garden crops.

SEAWEED FLIES Family Coelopidae Identification: Small to medium-sized, brown to blackish. Dorsum of thorax somewhat flattened, and body and legs very bristly. Sc complete.

Seaweed flies occur along the seashore, often in large numbers; larvae live in seaweed washed up on the shore. Adults occur around this seaweed, or on flowers and vegetation near the shore.


Identification: Small, usually shining black or purple flies, with head rounded and abdomen usually narrowed at base. Palps vestigial. Posterior spiracle of thorax with at least 1 bristle. Sc complete. Oral vibrissae lacking.

Larvae of these flies live in manure and similar materials, and adults are usually found around such materials. Sepsids are common flies and are often abundant around manure piles.

MARSH FLIES Family Sciomyzidae See also PL 14

Identification: Small to medium-sized, usually yellowish or brownish, often with spotted or patterned wings. Sc complete. Ri usually ends at middle of wing. Oral vibrissae absent. Post-verticals slightly divergent. Preapical tibial bristles present. Antennae generally project forward, often long. Femora with bristles, and middle femur usually with a characteristic bristle near middle of anterior surface.

Marsh flies are common insects that occur in marshy areas near ponds and streams. Larvae feed on aquatic snails, usually as predators.

DRYOMYZID FLIES Family Dryomyzidae

Identification: Yellowish or brownish, similar to Sciomyzidae but antennae usually not projecting, Ri ending beyond middle of wing, and femoral bristles not developed. 3rd antennal segment longer than wide, more or less flattened laterally.

Dryomyzids are small to medium-sized and often have brownish spots on the cross veins. They occur in moist woods

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