[1][3][4] These screwworms are referred to as "secondary" because they typically infest wounds after invasion by primary myiasis-causing flies.

While these flies carry many various types of Salmonella and viruses like the swine influenza, C. macellaria can also serve as important decomposers in our ecosystem.

[7] Cochliomyia macellaria are classified as intermediate sized flies with a dull or bright metallic, blue-green coloration.

[9] Despite the high concentration in these states, these flies have been found as far north as Southern Canada and as south as the Neotropics, with the exclusion of countries like Chile and Argentina.

[6] The larval stage of C. macellaria is referred to by the common name of secondary screwworms; this is due to the presence of small spines on each body segment that resemble parts of a screw.

[10] C. macellaria, unlike like C. hominivorax, do not have pigmented tracheal trunks; instead, they have V-shaped spines on the anal protuberance.

[8][10][11] Cochliomyia macellaria larvae will feed on the decaying flesh of the animal that they have been laid on until they reach maturity.

The entire larval stage is about four to seven days long, and afterwards, the larvae fall off the food source to pupate in the top layer of the soil.

[10] The C. macellaria larvae will typically burrow underneath the top layer of soil, leaves, garbage and begin to pupate there.

[15] Adult C. macellaria are considered to be medium-sized flies because they are about 6 to 9 mm in size and appear bright metallic blue-green to blueish purple in color.

[9][15] Within four days of emerging from the pupa stage, the adult C. macellaria become sexually mature and start looking for mates.

The males will typically mate rapidly and will spend most of their time eating nearby vegetation and nectar from flowers.

[15] During the larval stage, the C. macellaria will dig deeper into the necrotic wounds of their host animal and feed on the dead tissue.

[15] This time period is extremely crucial to the flies, as they must gather enough nutrients in order to last through the pupal stage without any food sources.

Males, at this point, will no longer consume tissue, but instead will eat nearby vegetation and intake nutrients from the nectar of flowers.

Adult female C. macellaria have been observed to will release pheromones that will stimulate the males copulatory attempts on contact.

Even though depriving the C. macellaria adults of dietary proteins did not impact the potency of the female extracts, there was a reduced response in males for the pheromones.

[10] The livestock industry considers the secondary screwworm an important pest because of the enormous economic losses caused by cases of myiasis and disease transmission.

[18] Cochliomyia macellaria is the most common species of blow flies found on carrion in the southern United States.

[18] Since the analysis of the succession and occurrence has been well defined, it is possible to create postmortem interval estimations, which are crucial for forensic entomology.

[18] Adult C. macellaria in the southeastern United States are only attracted to the dead tissue on animals minutes after the death.