Cucullia intermedia Speyer
Diagnosis: Cucullia intermedia superficially
resembles the various members of the speyeri complex. The forewing
is uniform gray with little or no significant maculation. Two main differences
separate intermedia from the species in the speyeri
complex. First, the hindwing is a uniform, medium brown color. The base
of the hindwing (at least) is white in the speyeri complex and
distinctly lighter than the outer margin. Indeed the male hindwing in
the speyeri complex is almost always entirely white except for
the outer margin. Second, the black streak in the forewing tornus of the
speyeri complex is almost always absent in intermedia.
The male and female genitalia are described under the group heading.
Distribution: Cucullia intermedia occurs in most of Canada and the northern United States. It ranges as far south as Pennsylvania in the east. In the west it reaches northern California. In the Rocky Mountains it stretches as far south as the White Mountains in east-central Arizona and occurs commonly in Utah, Colorado, and northeastern Nevada. A single specimen from Nevada is much lighter than any other specimen I have examined except for two unusually pale individuals from Newfoundland collected with normally colored specimens. The species is absent from the Great Plains region of the United States, except for North Dakota and western South Dakota, and is absent from the southeastern quarter of the United States.
Adults have been collected in May, June, and July.
Identification Quality: Excellent
Larva: I have not seen any preserved larvae. Through the courtesy of J.D. Lafontaine I have examined color slides of both third and last instar larvae reared from Lactuca canadensis Linnaeus. The last instar larva is dull black. The most conspicuous feature is a series of salmon-orange patches the side of the body near the spiracles. These patches are roughly rectangular on the thoracic segments, but become more ovate on the abdominal ones. There is a dorsal series of much smaller salmon-orange spots on the thoracic segments and the first two abdominal segments. The prolegs are black. The head is black with two small white spots in the adfrontal area. The third instar larva looks much different than the last instar larva. The third instar larva is also black, but a conspicuous cream-white dorsal line and a nearly white spiracular line are present. The head is black with conspicuous lateral white patches.
Foodplants: Lintner (1876) records the larva of intermedia from Lactuca biennis (Asteraceae), commonly called tall blue lettuce. In a most perplexing foodplant switch, Prentice (1962) records lucifuga on white birch. I have seen the reared specimens and they are indeed this species. The species was collected 118 times from white birch so the record is unlikely to be accidental.
See diagnostics section at the top of this page