Species name: Ophyra spp.
Family: Muscidae

Members of the genus Ophyra are shining black and about two-thirds the size of a house fly. Unlike the house fly, the vein M1+2 of Ophyra does not bend near the tip of the wing (Figure 16E).

Ophyra are sometimes called dump flies. Their life stages and life cycle are very much like the house fly. Their white eggs resemble those of the house fly and are deposited in similar situations.

The larvae are cylindrical, tapered anteriorly and closely resemble the larvae of the house fly. The Ophyra larvae, however, have a slight tinge of yellow and tend to be more slender and more active than the house fly larvae.

The posterior spiracles are distinctive with each composed of three nearly parallel straight slits (Figure 6D).

The cephalopharyngeal skeleton differs from that of the house fly larvae, including the presence of slender dorsal wings of the pharyngeal sclerite and two slender mouthhooks (Figure 7D). The pupa has a pair of fairly prominent respiratory horns.

Ophyra breed in the same habitats as the house fly and on occasions may become very abundant, especially in poultry houses and around piles of dairy cattle manure.

The larvae of Ophyra are vigorous and prey on other fly larvae, including those of the house fly.

Ophyra larvae apparently inject a toxin into the prey, because the prey often appears to become paralyzed soon after being attacked. Because of this behavior, Ophyra have some role in reducing the numbers of house flies. However, both flies occur together in livestock facilities and excessive numbers of Ophyra may be nearly as annoying as equivalent numbers of house flies.

Ophyra have a preference for sunny sites and often are found resting (along with house flies) on vegetation around animal facilities.