5829 Fly Mimicking a Potter Wasp_dorsal

Four-lined Hornet Fly (Spilomyia sayi).

Striped abdomen fly looking like the potter wasps foraging nearby in size and color. In fact, I never noticed it was a fly until I looked at the photos. Around 1/2 inch long. Besides the pond at home, Regina, Saskatchewan, Canada. 4 August 2022

 

Spilomyia genus

Numbers: 11 spp. in our area, 17 in the New World(1)(2), >100 in Eurasia(3)

 

Size: 12-17 mm

 

Identification: good wasp mimics: pattern of pigment on eyes hides "fly eyes"; V-mark on thorax, short antennae

keys to spp. in(1)(4)

 

Range

Widespread in the New World & Eurasia(3); in our area, widespread but poorly represented in se. US: 4 spp. are eastern widespread, 4 western widespread, and 3 restricted to AZ-TX-OK(1)

 

Habitat: Larvae in water-filled tree holes

 

Season: Summer to fall

 

Remarks

mimics of social wasps, have habit of resting on the four posterior legs and waving front legs about in almost the same way that vespids move their antennae(5)

bugguide.net/node/view/3288

 

S. sayi

Size: 12-16 mm

Range: NB-AB south to NJ-KS(2)

Habitat: Larvae found in the decaying heartwood of deciduous trees.

 

Adults most commonly found around wetlands and sometimes encountered hilltopping(1)

 

Season: Jul-Oct in ON(3)

Done