Sap-run
Guides
Xylota annulifera
Longspine Leafwalker
Xylota annulifera, described by Bigot in 1884, is an uncommon syrphid fly occurring across Canada and the eastern United States. Adults are medium-sized hover flies measuring 7.5–11.8 mm, characterized by black bodies with yellow abdominal spots. The species belongs to a genus whose larvae develop under bark in sap runs, though specific larval biology for this species is not well documented. Adults feed on nectar and pollen from flowers, typical of the Syrphidae family.
Xylota quadrimaculata
Four-spotted Leafwalker
A common species of syrphid fly found in central and eastern North America. Adults are 8.2–11.3 mm long, black with distinctive yellow-orange spots on the abdomen. Unlike most flower flies, adults rarely visit flowers, instead feeding on pollen from leaf surfaces. The larvae develop in rotting wood under bark in sap runs.