Noctuidae - Agaristinae



Agaristinae New Genus 1 ridingsii Grote

"Alypia ridingsii"

Alypia ridingsii Grote, 1865, Proc. Ent. Soc. Philad., 3: 521, pl. 5, fig. 1.

Diagnosis: Agaristinae New Genus 1 ridingsii is a slightly smaller version of mariposa. The length of the forewing from its base to its apex is approximately 16.5 mm in mariposa, but only about 14 mm in ridingsii. The superficial appearance of ridingsii is close to that of mariposa. The most distinctive feature separating the two species is the black accenting on the forewing veins between the reniform mark and the postmedial line is ridingsii. These veins are not accented with black in mariposa. The coronal spines of the male genitalia of mariposa are restricted to the apex of the valve, but in ridingsii the coronal spines are very dense and stretch along the outer margin of the valve almost all the way to the position of the clasper. The clasper of ridingsii has two tooth-like projections on its inner surface. These tooth-like projections are absent in mariposa. The ovipositor lobes of mariposa are unmodified, but each ovipositor lobe of ridingsii is shaped like a slightly convoluted mushroom cap. The outer ring of the ostium characteristic of so may genera of the Agaristinae is absent in mariposa by represented by a small reminant in ridingsii. Wing length: mean = 13.80 mm, standard deviation = 0.43 mm, n = 10.

Distribution: This species has a much wider distribution than mariposa, occurring throughout much of the western United States and southern British Columbia. Agaristinae New Genus 0001 ridingsii occurs as far east as the eastern edge of the Rocky Mountains in Colorado, and has been collected in Arizona and Utah. The species occurs commonly throughout all of California and northward into Oregon, Idaho, Washington, and into southern British Columbia. Little or no variability exits in this species.

Adults have been collected in March, April, and May in California, and as late as June in the more northern and eastern portions of its range.

Identification Quality: Excellent

Larva: The larva has been described and figured by Comstock and Dammers (1942). Their description is repeated below.

"Ground color, mauve-black, shading off to a mauve-brown at the segmental junctures. Mid-dorsally in relation to each segmental juncture there is an irregularly shaped large silver-white quadrant, with two narrow mauve-brown bands on it. In the stigmatal area there is an irregular broad white longitudinal band, bearing black spots. This band develoops upward extensions on each side of the segmental junctures, and these extensions are blotched with yellow. Mid-dorsally on the first segment there is an ornage bar. Abdomen, light mauve-brown, in some examples nearly white with brown spots. Legs, black. Prolegs, mauve brown, with black ends. Crochets, brown. Spiracles, black. A number of moderately long white setae are scattered over the body. These all arise from black papillae [pinacula], all of which are located only on the black bands and spots. Head, predominantly black, but with a subquadrate yellow spot in the center of the clypeus, and a pair of sub-triangulate small yellow spots above it. There is a small yellow spot below and back of the ocelli. Labrum, light yellow. Base of antennae, light yellow, the distal segments black. Ocelli, black. A few short white setae are scattered over the head."

The mature larvae cut holes in reeds, cork, and yucca to pupate in, and the opening of the cavity is covered with chewed fragments. The larva pupated in late May, the adult emerging the following June.

Foodplants: Comstock and Dammers (1942) recorded the following foodplants: "Oenothera" bistorta (currently Camissonia bistorta, "Eulobus" californicus (currently Camissonia californica, "Oenothera" dentata (currently (Camissonia dentata, and Clarkia rhomboidea, all members of the Onagraceae. The larvae were recorded as feeding on the seed pods.

Agaristinae New Genus 1 ridingsii

Agaristinae New Genus 1 ridingsii might be confused with Alypia maccullochii. Both species have the veins following the reniform mark of the forewing accented with black. The absence of white scales along the outer margin of the eye and the lack of orange scales on the prothoracic leg will immediately identify ridingsii. In addition orbicular and reniform marks of maccullochii form a v-shaped structure with its apex on the inner margin of the forewing. The orbicular and reniform marks fuse with the trapezoidal inner margin patch to form a square structure in ridingsii and mariposa.

The differences between mariposa and ridingsii are listed in the species diagnostic section above.

Similar Species

Agaristinae New Genus 1 mariposa

Alypia maccullochii