[5] The larval form of the drone-fly, the rat-tailed maggot, is found on every continent except Antarctica, and ranges to the highest latitudes in the North.

[6] This species is not prevalent in extremely southern latitudes, neither is it common in arid areas of Europe, Asia, and Africa.

[7] Pigmentation has an important role in the control of body temperature; the black areas down the center of the drone-flies abdomen may absorb solar radiation and so warm the dorsal blood vessel, which is right underneath.

[6] When male E. tenax of the spring and summer generations stop dispersing, they settle within home ranges which provide them with locations suitable for sheltering, resting, basking, grooming, feeding and mating.

[10] But when it is on its mating site, the male is very territorial, attacking alien species such as bees, wasps, and butterflies.

[6] All drone-fly larvae have a siphon on their posterior end that acts as a respiratory mechanism and looks like a tail, hence the common name, rat-tail maggot.

[6] The adult drone-fly's body is dark brown to black in color, with yellow-orange marks on the side of the second section of the abdomen.

[6] There is sexual dimorphism in drone flies: males tend to have lighter patterns than females.

It lives in drainage ditches, pools around manure piles, sewage, and similar places where water is polluted with organic matter.

When fully grown, the larvae creep out into drier habitats, and seek a suitable place to pupate.

It looks somewhat like a drone honey bee, and likely gains some degree of protection from this resemblance to a stinging insect.

Like other hover flies, they are common visitors to flowers,[12] especially in late summer and autumn, and can be significant pollinators.

Under extremely rare conditions, there have been documented cases of human intestinal myiasis of the rat-tailed maggot (larva of Eristalis tenax).

The larva can survive, feeding on feces at this site, as long as the breathing tube reaches out from the anus, which is quite rare.

[6] This occurs when fly larvae inhabits a living host by accident, usually from ingestion of contaminated foods.

[15] There are still many gaps in the understanding of the drone fly life cycle, and more detailed research is needed.

[6] Females feed on pollen after they emerge from the pupa and that way they are able to get the nutrients they need to complete reproduction.

[6] The toughness and resilience of E. tenax increases with age; the skin is insoluble even in strong alkaline solutions.

[17] The thorax can be sliced open for examination, and the muscular bundles inside may still twitch when an irritant or needle-point is used.

[6] After mating, the adult female lays clusters of about 10 eggs near dirty, contaminated water, sewage, or decomposing organic substances.

[18] Bees are common models for several Dipteran mimics[7] They are similar in their general form, flight, and coloration.

[18] In both species branched hairs and spirally grooved bristles act as collectors and retainers of pollen, and leg-scraping that occurs during hovering allows the transfer of pollen to take place, from hind legs to front legs in E. tenax, and in the reverse direction in honey bees.

Common drone flies are active during much of the year, from March to December, and sometimes they are more numerous than honeybees, especially during autumn in urban areas.