Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Clickable Guide
Moths Butterflies Flies Caterpillars Flies Dragonflies Flies Mantids Cockroaches Bees and Wasps Walkingsticks Earwigs Ants Termites Hoppers and Kin Hoppers and Kin Beetles True Bugs Fleas Grasshoppers and Kin Ticks Spiders Scorpions Centipedes Millipedes

Upcoming Events

Photos of insects and people from the 2022 BugGuide gathering in New Mexico, July 20-24

National Moth Week was July 23-31, 2022! See moth submissions.

Photos of insects and people from the Spring 2021 gathering in Louisiana, April 28-May 2

Photos of insects and people from the 2019 gathering in Louisiana, July 25-27

Photos of insects and people from the 2018 gathering in Virginia, July 27-29

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Previous events


Family Xylophagidae

pointy-end underbark larvae - Xylophagus Xylophagidae (dorsal) - Xylophagus fly - Dialysis elongata - female fly - Xylophagus lugens - female Fly being Eaten - Rachicerus obscuripennis Xylophagidae - Xylophagus lugens Coenomyia ferruginea awl fly - Dialysis elongata - female
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Diptera (Flies)
No Taxon (Orthorrhapha)
Family Xylophagidae
Explanation of Names
Xylophagidae Fallén 1810

Comes from "xylophagous," meaning wood-boring.
23 spp. in 6 genera in our area(1), ~150 spp. in 15 genera total(2)
2-25 mm(1)
Slender-bodied without prominent hair. Usually black, but sometimes marked with yellow, or nearly all yellow (1). Facial orbits and cheeks not sutured (3). Calypters (lobes on base of wing along trailing edge) small or absent. Third antennal segment is elongated, execept in Rachicerus, where the antennae appear to have many segments.
Vertex flush with eyes or slightly depressed, eyes widely separated in both sexes, antennal flagellum with an apical arista, or with 8 or 20-36 flagellomeres, pectinate, subpectinate, or serrate, clypeus recessed in a deep facial groove and flattened, in profile with anterior surface depressed below level of parafacial, and not reaching dorsally to bases of antennae
Scutellum usually unarmed, large, convex with a hairy disc, evenly rounded apically, subscutellum absent or very weakly developed; posterior thoracic spiracle never with a scale-like elevation immediately behind it
Legs slender, tibial spur formula 1-2-2, fore tibia with a ventral apical spur, precoxal bridge absent, empodia pulvilliform
Wings always present, C either extending to slightly beyond wing apex, or, as in most taxa, continued around the wing, branches of R and M diverging to apical wing margin, branches of M joining margin well below apex of wing, without a composite ‘diagonal vein’, branches of R not crowded anteriorly, Rs arising well before base of cell d, R2+3 ending at C near R1, R5 ending at or beyond wing apex, crossvein r-m close to base of cell d, cell d large, at least as close to posterior margin as to anterior margin of wing, at least 2 times as long as broad, M usually 3 branched, CuA, free or meeting A, in an acute angle near wing margin, anal lobe and alula well developed, calypters small
Wing venation:
much of the world (none in the Afrotropical Region)(4); mostly northern NA(1)
Typically woodlands; larvae on decaying vegetation, under bark, or in decaying wood(1)
Adults sometimes take nectar and other fluids(1)
Life Cycle
Larvae scavengers or predators(1). Xylophagus larvae may prey on bark beetle larvae
Possibly sister to the Tabanomorpha.
Print References
Shin S, Bayless KM, Winterton SL, Dikow T, Lessard BD, Yeates DK, Wiegmann BM, Trautwein MD (2018) Taxon sampling to address an ancient rapid radiation: a supermatrix phylogeny of early brachyceran flies (Diptera). Systematic entomology, 43, 277–289. doi:10.1111/syen.12275.