Ottawa (Dunrobin), ON Canada

29 May 2002   1:08AM EST  (top left)
5 June 2002   11:44PM EST  (top right)
28 May 2002   1:26AM EST  (bottom left)
23 May 2002   11:12PM EST  (bottom right)

Heterocampa guttivitta is one of several species of Heterocampa that may occur in my general area, some of which are quite similar to each other.  Heterocampa guttivitta, in particular, is easy to confuse with Heterocampa biundata (7995), which is also illustrated on this web site.  Thanks to Dr. A.W. Thomas (formerly of NRCAN) and Dr. J. Donald Lafontaine (Agriculture Canada), I also learned that both these Heterocampa species have quite a green color when fresh, but tend to look much more gray or brown in older specimens.  In general, Heterocampa guttivitta is smaller, less bulky and a little more mottled than Heterocampa biundata.  While I am fairly confident that I've correctly identified the specimens illustrated and referred to on this web page, there remain a number of unidentified photographs in my files that are simply labeled as Heterocampa.

The forewing of Heterocampa guttivitta is overall a deep greenish color shaded with gray in fresher specimens (top and bottom left, above), but appears more brownish in older specimens (top and bottom right, above).  Most of the markings are usually indistinct.  In the two top photos, it is possible to make out the double zigzag antemedial line, outlined in black with greenish to brownish filling.  The first photo also shows a fairly distinct postmedial line, double, scalloped and filled with green, but in the other photos, the main evidence of this line is the lighter marking at the inner margin above the anal angle.  In the fresher specimens at left, the subterminal line also shows fairly clearly as a line of black spots.  According to Covell (1984) the reniform spot appears as a black crescent in a light gray oval, but this marking does not stand out on any of the specimens shown above.

The hindwing is gray, patterned at its leading edge as if to extend the am and pm lines of the forewing.  In the last photo, this edge of the hindwing can be seen protruding beyond the costa of the forewing (compare the same feature in Peridea angulosa (7920) and Peridea ferruginea (7921)), where the moth is resting in a slightly flattened version of the peaked roof shape characteristic of the Notodontidae.

The appearance of the larva of Heterocampa guttivitta gives rise to the species' common name of Saddled Prominent.  The larvae feed on a variety of deciduous trees, including birch, maple, beech, elm, oak and others.  Periodically an outbreak of this species can result in significant defoliation of mixed hardwood forest.  Handfield (1999) indicates a flight period for the adult moth from about mid-May to about mid-July in my general area.

I have photographed this species in 2001 on 9 and 10 May; in 2002, on 23, 27, 28, 29 and 30 May, and on 2 and 5 June.