Diario de murphyslab

Notes on Sicya crocearia & Sicya macularia

I'm trying to figure out what distinguishes Sicya crocearia from Sicya macularia. It seems that there may not be any visual cues that clearly distinguish the two species in their adult forms.

Online Reference Comparison

Sicya crocearia

Usual online references:

Sicya macularia

Usual online references:

Notes

A quick glance at two DNA barcode, one for each species. They were identical.
Between the two sets in the C.P. Gillette Museum's collection where images are available, there might be a small difference: Among the specimens labelled S. crocearia the following features appear unique to the set, although not present in all examples:
1. Forewing: Sharper discontinuity in the terminal band, where it transitions from reddish brown to yellow perpendicular to the length of the wing.
2. Forewing: The terminal band widens more at the costa.
3. Forewing: Inner reddish brown band widens more at the inner edge.
(Only the 3rd feature seems consistent with the MPG photos.)

References

Parsons, 1999 in Geometrid moths of the world : a catalogue (Lepidoptera, Geometridae)
https://ftp.funet.fi/pub/sci/bio/life/insecta/lepidoptera/ditrysia/geometroidea/geometridae/ennominae/sicya/
McGuffin, W. C. (1977). GUIDE TO THE GEOMETRIDAE OF CANADA (LEPIDOPTERA): II. SUBFAMILY ENNOMINAE. Memoirs of the Entomological Society of Canada, 109(S101), 1–191. doi:10.4039/entm109101fv
MPG: Geometridae: Ourapterygini
https://bugguide.net/node/view/26031/bgref (are any specific?)

Pohl 2018

Greg R. Pohl, et al. in Annotated checklist of the moths and butterflies (Lepidoptera) of Canada and Alaska, 2018.

Suggests that S. crocearia might not be a distinct species:

Sicya Guenée, 1857

crocearia Packard, 1873 (Sicya)

NOTE: This taxon may not be sufficiently distinct from S. macularia to warrant status as a separate species, but it is retained here pending further work.

VNHS Blog

The problem with Sicya is that there seems no general agreement as to whether S. macularia and S. crocearia are truly separate species, or whether they should be lumped as one. Jeremy Tatum writes: Unlike the case for iridopsis, I have no opinion one way or the other. In looking at published pictures of aduilts [sic] and larvae, I see conflicting evidence. In the adults, there seems to be no consistent reliable feature for telling one from the other, so I would say they are all one species. On the other hand, there seem to be two distinct caterpillars, suggesting that they are separate species. I’ll label Jochen’s moth with an either/or.

Sicya macularia/crocearia (Lep.: Geometridae) Jochen Möhr

Source: "July 16 evening" (blog post), Victoria Natural History Society, Victoria, British Columbia.

LepIndex

https://www.nhm.ac.uk/our-science/data/lepindex/detail/?taxonno=245892

Original Descriptions

Sicya macularia Harris 1850

Ennomos macularia, 1850

forewings: rust-brown costal spot near the shoulders
a transverse row of spots near the base
a stigmatical dot
three little spots near the tip
a very large lozenge-shaped spot at the anal angle, of the same brown color
the large spot being bordered before and behind with darker brown

Sicya crocearia Packard 1873

https://www.gbif.org/occurrence/1836945295
Syntype
Alpheus S. Packard, Jr. in Catalogue of the Phalaenidae of California. No. 2. Proceedings of the Boston Society of Natural History 16:13–40., 1873.
sulphur yellow
primaries crossed y two light brown lines
inner line oblique, scarecely curved, and bent at right angles on the costa
the outer runs straight from just beyond the middle of the inner edge of the wing to the costa, on which it forks, ending just before the apex; beyond this line the wing is pale fawn brown, the apical region clear yellow.
hind wings with a single sinuate reddish or brown line, beyond which the wing is tinged with reddish, while within the line it is inclined to be whitish.