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Blow fly, Bottle fly

Calliphora spp
Phaenicia spp., etc.

Class: Insecta
Order: Diptera
Family: Calliphoridae

Blow fly and bottle fly adults are about 1/8-5/8 in (4-16 mm) long, the size of a house fly, or slightly larger. Mature larvae are about 3/8-7/8 in (9-22 mm) long.

Blow flies and bottle flies have sponging mouthparts; antennae are feathery, at least on the bottom two thirds. Larvae are eyeless, legless, tapered from large, rounded rear segment to head, which is a pair of dark hooks.

Adults are partly or wholly metallic blue, green, or dull brassy, sometimes black. Larvae are pale yellow to white.

Comparison with other species
Cluster fly has a dull body, tan to brownish black, with golden hairs on thorax. Secondary screwworm fly has bluish green body, orange head, reddish legs, and 3 black stripes on thorax. Screwworm fly has metallic black body, legs shiny green-black, 3 black stripes on thorax (middle one shorter). Dump flies have bluish black to shiny and bronzy black body. Flesh fly and House fly have dull gray and black bodies, and thorax with 3 or 4 black stripes.

Same as food source!

Meat; animal carcasses, especially those of birds and other small animals; excrement; decaying vegetation; garbage.

Females lay their eggs on material which larvae will eat. Larvae may feed on the surface, then burrow into less decayed material underneath. They go through 3 instars, leaving the food material in order to pupate. Most species pupate within the top 2″ of soil. Usually they overwinter as mature larvae or pupae. Development time from egg to adult varies, depending on species and temperature conditions, but usually takes between 10 to 25 days.

Bottle flies and blow flies transmit disease.

Blow and bottle flies are most active on warm, sunny days. They rest on cool or cloudy days. They are attracted to light coming through windows. Some species are strong fliers, such as some black blow flies that were found 4-28 miles from their starting point.