Owlfly

Family of insects
Automatic taxobox
| fossil range =
| image = Owlfly (Libelloides macaronius) female Istria. jpg
| image2 = Owlfly (Libelloides macaronius) female Istria 2. jpg
| image2 caption = both female Libelloides macaroniusIstria, Croatia
| taxon = Ascalaphidae
| authority = Rambur, 1842
| subdivision ranks = Subfamilies
| subdivision =
Albardiinae
Ascalaphinae
Haplogleniinae
Melambrotinae
Ululodinae
and see text
| subdivision ref = All but one species of Ascalaphidae have long antennae, easily distinguishing them. The sole exception is the Brazilian Albardia furcata, the only living member of the subfamily Albardiinae, which has short antennae, but these are strongly clubbed (compared to myrmeleontids), and its wing venation is reticulate, typical of ascalaphids. Most owlflies are about in length, not including antennae.

[[File:Owlfly. JPG|thumb|upright|Some owlflies raise the abdomen at rest, mimicking a broken twig. The larvae too are predatory, making owlflies important in maintaining a natural ecological balance and helping to control pest insects. Adults of many New World species are most active at sunset, and can often be collected near lights. During the day, adults rest on stems and twigs with the body, legs, and antennae typically pressed to the stem. Some Old World species, such as Libelloides macaronius, are active during the day.

When disturbed, some owlflies release a strong, musk like chemical to deter enemies. or as heliographic signalling, reflecting sunlight, to attract females.

Owlflies appear to have evolved from a common ancestor with Stilbopterygidae. These, in turn, evolved from a common ancestor with Palparidae, which evolved from a common ancestor with the true antlions, or Myrmeleontidae. The name is from Greek askalaphos, a kind of owl. In Greek mythology, Ascalaphos was the custodian of the orchard of Hades, god of the underworld; the goddess Demeter transformed him into an owl.

The owlflies are known from fossils of adults and larvae, often encased in Baltic amber. Most of these cannot be placed in a particular subfamily. Most are known from the Oligocene. The Late Jurassic Mesascalaphus was thought to be a more basal member of the family, but it is now believed to be a member of Mesochrysopidae.

Total evidence analysis (several genes + morphology) in 2019 recovered Ascalaphidae as monophyletic and found evidence for five subfamilies: Albardiinae van der Weele, 1909; Ululodinae van der Weele, 1909; Haplogleniinae Newman, 1853; Melambrotinae Tjeder, 1992; and Ascalaphinae Lefèbvre, 1842. Molecular analysis in 2018 using mitochondrial rRNA and mitogenomic data also placed the Ascalaphidae as sister to the Myrmeleontidae as the most advanced groups within the Neuroptera. The fossil record has contributed to an understanding of the group's phylogeny. The phylogeny of the owlflies has remained uncertain, with many of the higher taxa apparently not natural groups (clades).

Neuropteran subfamilies are described in Winterton and colleagues 2017 and Jones 2019.