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Genus Dichorda

Illinois entry - Dichorda iridaria Showy Emerald Moth - Dichorda iridaria Emerald Geometer - Dichorda illustraria Green Moth - Dichorda illustraria - female Showy Emerald  - Dichorda iridaria Dichorda iridaria - Showy Emerald - Dichorda iridaria dichorda - Dichorda iridaria Arizona Moth - Dichorda rectaria
Show images of: caterpillars · adults · both
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Lepidoptera (Butterflies and Moths)
Superfamily Geometroidea (Geometrid and Swallowtail Moths)
Family Geometridae (Geometrid Moths)
Subfamily Geometrinae (Emeralds)
Tribe Nemoriini
Genus Dichorda
Synonyms and other taxonomic changes
Dichorda Warren, 1900
Numbers
There are about 9 species in the genus and 4 species in NA. (1)(2)
Identification
Adults:
Check the ranges first. Some species have very restricted ranges. The three species in the west have some overlap in range. (see below)
Eastern half of North America:
The Showy Emerald Moth, Dichorda iridaria usually has lots of white streaking on both wings and some whitish suffusion in the median area.

Central and Western USA: Texas to North Dakota and west to Idaho and California. (3)
They are similar to Dichorda iridaria and Dichorda consequaria but lack any whitish suffusion in the median area. Transverse lines are rather bold and fairly straight. (3)

South-western: (southern AZ)
Wide white transverse lines are straight and often have white shading.
Forewing outer margin is less convex and appear more pointed than N. iridaria.
Forewing ventral (underside) postmedial line is usually double. (single in N. iridaria).
Forewing veins beyond the postmedial are usually streaked with white; much less so in N. iridaria. (4), (3)

Western: (AZ, CA, OR)

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Larvae:
Dichorda iridaria
Dichorda consequaria
See Also
The Phoenix Emerald Moth, Dichordophora phoenix is very similar. Check the ratio of the band-widths along the costal edges of the fore-wings. (median band/PM band) = less than 2.5 in that species


The lack of colored abdominal spots and the angle of the PM lines should help to rule out Nemoria caerulescens and Nemoria obliqua, as well as others in that genus.
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Works Cited
1.Wikipedia
2.North American Moth Photographers Group
3.The Moths of America North of Mexico Fascicle 18.1. Geometroidea, Geometridae (Part), Geometrinae
Douglas C. Ferguson . 1985. The Wedge Entomological Research Foundation.
4. A revision of the moths of the subfamily Geometrinae of America north of Mexico (Insecta, Lepidoptera)
Douglas C. Ferguson. 1969. Peabody Museum of Natural History Yale University Bulletin 29.