Catocala ultronia
Updated as per E.H. Strickland Entomological Museum, Dept. of Bio. Sc., U. of Alberta, Nov. 2007.
Updated as per Noctuidae of Western Canada, Canadian Biodiversity Information Facility, Nov 2007

Catocala ultronia
(Hubner, 1823) Eunetis ultronia

Catocala ultronia, courtesy of James Adams.

This site has been created by Bill Oehlke at
Comments, suggestions and/or additional information are welcomed by Bill.


Superfamily: Noctuoidea
Family: Noctuidae
Group: Noctuinina
Subfamily: Catocalinae
Genus: Catocala, Schrank, 1802
species: 8857 ultronia


"Moon River"
copyright C. Odenkirk

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Catocala ultronia, the Ultronia Underwing, (wingspan: 50-63mm) flies from extreme southeastern British Columbia and Alberta to Manitoba to Nova Scotia and Prince Edward Island, Canada, south through New Hampshire, Connecticut, Tennessee, etc., to Florida and west to Texas and Oklahoma. Tom Middagh reports them in Minnesota. Harry D. King reports them in Michigan.

Catocala ultroni form celia, bait, Mason, Ingham County, Michigan,
July 7, 1994. courtesy of Harry King.

Catocala ultroni form celia (verso), bait, Mason, Ingham County, Michigan,
July 7, 1994. courtesy of Harry King.

Occasionally the lower wings will be yellow instead of orange.

There is considerable variation in forewing pattern as shown in this specimen from Ontario, courtesy of Lynn Scott, the specimen from Marion County, Florida, courtesy of Leroy Simon and in the three specimens courtesy of Vernon A. Brou at botom.

Catocala ultronia courtesy of Lynn Scott

Catocala ultronia courtesy of Leroy Simon

The forewings are typically gray-brown, with a dark lower margin and a characteristic brown patch near the wingtip.

The hind tarsi have three rows of spines. The outer wing margin (lower wings) is heavily barred with a pure white patch at the apex.

Catocala ultronia, Peterborough, Ontario, July 22, courtesy of Tim Dyson.

Catocala ultronia undersides, Peterborough, Ontario, July 27, 2006 courtesy of Tim Dyson.

Visit Catocala ultronia, June 30, 2008, Montgomery County, Tennessee, in Tom Payne Tennessee Catocala Collection.


In Quebec and Ontario Catocala ultronia flies from early July to late September. Deb Lievens reports Catocala ultronia on the wing in Rockingham County, New Hampshire, from August 4 - September 22.

In Concan, Texas, moths have been taken in late April.

Tim Dyson of Ontario, Canada, sent me this nice image copyright of an apparent Catocala "fan". Tim has been using some red wine in his bait (August 14), but "me thinks" the "frog" is happy for other reasons.

Moths come in to lights readily and also to bait.

Catocala ultronia, Catocala muliercula and Catocala minuta on fermenting tree sap
courtesy of Steve Walter, Floyd Bennet Field (Jamaica Bay area of New York) July 6.

Steve writes, "The Little Wife is one of the signature species of Jamaica Bay -- but this one was 11 days (seems to be a magic number, or times 2) earlier than the previous early date here. The Little Underwing was new for Jamaica Bay -- and I had 6 of them. Funny how that happens."

The Catocala ultronia caterpillar shows a preference for members of the Rosaceae family: Malus (apple), Prunus pensylvanica (pin cherry), Prunus serotina (wild black cherry), Prunus virginiana (choke cherry), Fraxinus pennsylvanica (green ash), Tilia americana (American basswood, American linden) and Populus grandidentata (Big Tooth Aspen).


Adults eclose from pupae amongst ground litter or near the soil surface.

Usually when adults alight on a vertical surface, they align themselves with bodies vertical (ultronia rest with head down). I wonder if this specimen is trying to take advantage of the horizontal grey mortar line.

Image courtesy of Lynn Scott.


Catocala ultronia females emit an airbourne pheromone and males use their antennae to track the scent plume.


Grey, cushion shaped, sculptured eggs are deposited on tree bark in the fall and hatch the following spring.

Note the prominent horn on the fifth abdominal segment. There is a distinct black line on top of head and an oblique black line running (anterior) from base of the slightly enlarged dorsal scoli of eight abdominal segment.

Dense and relatively long fringe and body are grey.

Image courtesy of David Wagner.

Larval Food Plants

Listed below are primary food plant(s) and alternate food plants. It is hoped that this alphabetical listing followed by the common name of the foodplant will prove useful. The list is not exhaustive, although some species seem very host specific. Experimenting with closely related foodplants is worthwhile.

Fraxinus pennsylvanica.....
Populus grandidenta
Prunus pensylvanica
Prunus serotina
Prunus virginiana
Tilia americana

Green ash
Big Tooth Aspen
Pin cherry
Wild black cherry
Choke cherry
American basswood, American linden

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