Bibio marci

Common name: St Mark's Fly
Scientific name: Bibio marci
Genus: Bibio 毛蚋屬
Family: Bibionidae 毛蚋科, St Mark's flies
Suborder: Nematocera 長角亞目
Order: Diptera 雙翅目, true flies

Remarks: The St Mark's fly, or 'hawthorn fly, is a very common, long, shiny, black fly that can be found in large numbers during the spring around woodland edges, fields and wetlands. It is so-called because it emerges around St Mark's Day, April 25th. It hangs in the air over the vegetation, drifting along with its legs dangling underneath it. Large numbers of adults can be found in woodland edges, hedgerows, fields and wetlands.

The larvae live in the soil feeding on roots, grasses and rotting vegetation, and are often found around compost heaps. The adults feed on nectar and are considered to be important pollinators for fruit trees and other plants.

Status: Common

Date: 13th April 

All the photos below are male with large bulbous eyes (vs smaller head bad eyes in female)

194 Body black, hairy; legs all black. 

228 Pollens on the body.

231 Side view showing the legs.

227

227_1 Note the front tibia 脛節 with a pair of large spurs (vs front tibia with a circlet of small spines in Dilophus)

124

123