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Ottawa (Dunrobin), ON Canada
30 May 2004 8:53PM EST (top)
4 June 2005 11:27PM EST (bottom)
Agrotis stigmosa is one of seven species of Agrotis
recorded from the Ottawa area (J.D. Lafontaine, pers. comm., 2001), five of
which are illustrated on this website. Having seen relatively few
specimens, I find it somewhat difficult to distinguish Agrotis stigmosa
from specimens of Agrotis volubilis (Hodges 10659) and Agrotis obliqua
(Hodges 10660), and I am grateful to Mr. James T. Troubridge of Agriculture
Canada for confirming my identifications of the specimens illustrated above.
The forewing of Agrotis stigmosa is brownish, quite
light in color, and variably with a grayish, yellowish, or pinkish tone.
Dark gray to blackish shading along the costa
extends nearly to the apex, but does not completely surround the orbicular and
reniform spots. Antemedial and postmedial lines are at least partially
evident. A dash extends from the base of the forewing to a short distance
outside the am line, usually with a clear black outline, but without a solid
dark filling.
The orbicular and reniform spots are fairly dark, often surrounded by a paler
outline inside a fine black outline. In the subterminal area, there may be
short fine dark streaks marking some veins immediately outside the scallops of
the pm line; there may also be some sharp points of white extending inward from
the outer margin, especially in the vicinity of a dark patch about a third of
the way along the outer margin below the apex. The thorax is brownish with
paler tegulae. The hindwing is grayish brown with a pale fringe.
The grayish brown hindwing is potentially a useful aid for
differentiating Agrotis stigmosa from Agrotis volubilis, which has
a whitish hindwing. To distinguish Agrotis stigmosa from Agrotis
obliqua, it is more useful to look at the differences in forewing color and
pattern, Agrotis stigmosa being lighter in ground color, with less dark
costal shading, for example. It is not always possible to differentiate
these species without a thorough examination of the specimen, however.
According to Handfield (1999), the host plant for Agrotis
stigmosa is unknown. For my general area, he indicates an adult flight season from
about mid-May to mid-June.
My records to date for Agrotis stigmosa (each date
representing "the night of") are in the table below: |
