Other Common Names
Drone Flies (sometimes applied to E. tenax only), Rat-tailed Maggots (larvae of E. tenax)
Synonyms and other taxonomic changes
Explanation of Names
Latin
eristalis, a kind of gemstone, maybe
opal (likely what Latreille meant)
Numbers
2 subgenera, with 20 spp. in our area
(2) and ~100 total
(3)Identification
Some species (e.g., E. tenax) resemble honey bees. Others are darker, less hairy, e.g. E. dimidiatus, E. nemorum.
Wing
Keys to species by Bill Dean at
Larva's anterior spiracles dark brown; prolegs with crochets in three rows with spicules gradually becoming smaller below
Range
Holarctic, Neotropical, Afrotropical, Oriental
(3);
E. tenax is introduced from Europe
Food
Adults take nectar. Larvae feed on small organisms in stagnant water.
Life Cycle
Larvae, at least of E. tenax, live in eutrophic water, have tail that serves as "snorkel" for breathing. They are called rat-tailed maggots.
Larva, puparium, female ovipositing
Remarks
Eggs of E. tenax are occasionally swallowed by humans and the larvae live in the human intestinal tract, where they cause "myiasis". E. tenax sometimes emerges from carrion, closely resembles honey bee. This may account for the biblical story of honeybees nesting in a dead lion.
