Ottawa (Dunrobin), ON Canada

1 August 2005   9:53PM EST  (top)
27 July 2004   10:30PM EST  (center left)
7 June 2005   10:12PM EST  (center right)
13 June 2004   8:43PM EST  (bottom left)
7 August 2003   10:26PM EST  (bottom right)

My initial identification of Munroessa icciusalis was based on Covell (1984), and subsequently checked against Munroe, E., The Moths of North America North of Mexico, Fascicle 13.1, Pyraloidea Pyralidae (Part) (London: E.W. Classey, 1972-1974) and by comparison of photographs and specimens with those in the Canadian National Collection in Ottawa.

Munroessa icciusalis has wings patterned in buffy yellow, black and white.  The dominant color on both forewing and hindwing is yellow, sometimes quite bright, but often a dull, light yellowish brown or buff.  On the forewing, much of the white occurs in the median, typically with two irregular white areas at the costa and a round white spot in the lower half of the median.  These white areas are partially bordered with dark brown to black lines.  There is also an irregular white subterminal band, bordered in dark brown to black along its outer edge.  The hindwing pattern is similar, but without the round white spot in the median.  The fringe on both wings is somewhat checkered with yellowish buff, white and brown.  The abdomen is whitish, with yellow stripes.  There is considerable variability from one specimen to another, and Munroe (1972) notes that the black lines seem to be better developed in southern specimens than in northern ones.  Covell (1984) indicates a wingspan ranging from 1.6 to 2.6 cm for this species.

According to Covell (1984), the larvae of Munroessa icciusalis make cases out of plant parts, and feed on a variety of aquatic plants including buckbean, duckweed, eelgrass, pondweeds and sedges.

My records to date for Munroessa icciusalis (each date representing "the night of") are in the table below: