Metallic Stem Borer
Head: Metallic black, top of head metallic gray. Nose cone (palpi) white, tips dark.
Antenna: Long, reaching to wing tips. Metallic black.
Thorax: Metallic gray to black.
Wings: Forewing, except base entirely orange. Base metallic gray to black, with an irregular border, sometimes appearing as an additional metallic gray spot. Five raised metallic gray oblong spots along outside (costal) edge and 3 raised metallic gray spots along inner margin from mid-wing to anal angle. Fringe gray, metallic whitish along inner edge to anal angle. Hindwing black with gray fringe.
Legs: Metallic black with some metallic gray streaks.
Abdomen: Metallic black, more brassy on male; whitish tip.
Similar Species: All others have white antenna tips:
Neoheliodines cliffordi has a wide black stripe from thorax tip to first set of metallic silver spots and black, irregular-shaped wing tip.
Chrysoclista villella has outer (costal) half of base of wing black. 1st silver spot on inner margin has black tuft. White spot on costal fringe.
Chrysoclista linneella has orange wing colour surrounded with black; 3 silvery spots.
Mompha terminella has dark wing tips and black tufts at mid-wing.
Euclemensia bassettella has a wide black inner margin from mid-wing to tip. Antenna last 1/3 white.
Neoheliodines nyctaginella (not in Ontario) has a black line around tip of thorax (technically inner margin of wing base). Except for white antenna tips, almost identical to Embola ionis.
Size: About 5 to 6 mm long. Wingspan 9 to 12 mm.
Habitat: Meadows and forest edges.
Food: Adults – flower nectar, especially Fleabane. Larvae feed on Wild Four O’clocks Mirabilis nyctaginea.
Flight Time: Mid-June to mid-July in Ontario.
Life Cycle: Female deposits pinkish-orange eggs on side of axillary buds. Larva enter stems and tunnel down. 6 instars if over-wintering, 5 if not. Pupates in the stem. Over-winters as half-grown larvae. Larvae are waxy, whitish with dark head and collar (cervical shield). Mature larvae have spotted abdomens, and just before pupating, they become entirely yellow. Pupate in tunnel after 25 days. Embola ionis adult does not raise its hind legs when resting. 3 generations per year in Illinois, probably only 1 or 2 in Ontario.
Comments: One found at Point Pelee on Jun 22, 2010. Listed as new to Canada per Pohl (2018). Wheatley 2007 & 2014.
Synonyms: Clarke 1952
Proceedings of the Entomological Society of Washington, 1952, Vol. 54 #3 by Clarke, pg. 138.
Proceedings of the Entomological Society of Washington, 1956, Vol. 58 #1 by Webster, pp. 43-46.
University of California Publications, Entomology, 2005, Vol. 124 by Hsu & Powell, pp. 58 to 60.
Holotype as Heliodines ionis male by Clarke, 1952. Type Locality: Illinois. In the United States National Museum of Natural History, Washington, D.C. Type #61496.