Update, July 31, 2007: I showed the photo to Jim Z. last Thursday, and he said that it’s a Southern with a darker than usual face. He had had only a brief view in the field. Digital cameras are truly a butterflier’s friend.
I’ve been on the web looking at photos and reading descriptions of Northern and Southern Cloudywings and have also reviewed the photos in Glassberg; Kaufman; and Heitzman. The result is that I’m still in doubt about the identification of the cloudywing Jim Z. and I saw last weekend.
Descriptions
All emphases are the authors’.
Face
The Horseshoe Lake (HL) individual, pictured in the previous post, clearly lacks the extremely light lower side of the face of the Southerns shown in Glassberg and Kaufman. Glassberg describes the face of the Southern as “white or pale gray” (p. 150), whereas Kaufman describes it as “often pale” (p. 260); Heitzman doesn’t mention the face, and his photos are of the dorsal side of specimens.
Of the Northern’s face, Glassberg says that it is “dark brown or dark gray”, and Kaufman says that it is “often dark”.
Antennal club
Both Glassberg and Kaufman mention white at the bend of the antennal club. Glassberg: “Southern Cloudywings have a white patch just where the antennal clubs bend,…” Kaufman: “[A]ntennal clubs may have a white spot at the bend.” Both mention the absence of a white patch in the Northern. Heitzman doesn’t mention the white patch or its absence.
Both Kaufman and Heitzman mention the costal fold in the Northern and its absence in the Southern. Because I have no idea what the costal fold looks like, despite having looked at the diagrams in the guides of the three authors and at images on the internet, I don’t know whether or not the HL cloudywing has one.
Wing spots
Glassberg describes the wing spots of the two cloudywings as follows:
Southern Cloudywings have more extensive and aligned spots than do Northern Cloudywings. Note especially the 2nd spot from the FW margin. This spot is prominent and hourglassed [sic] shaped in Southern Cloudywings but is usually a small dot or absent in Northern Cloudywings.
Kaufman, Southern:
Above dark brown with glassy white spotband on forewing broad and aligned. Row of small white spots near tip of forewing forms a straight line (summer) or has the bottom spot slightly offset outward (spring).
Kaufman, Northern:
Above dark brown with tiny triangular white spots on forewing reduced and not aligned with each other.
The second spot from the forewing margin in the HL cloudywing is prominent, but looks only vaguely hourglass shaped to me.
Internet findings
- Identified as a Northern (right-hand photo)—the face looks roughly as dark as that the HL cloudywing:
- www.birdsofoklahoma.net/NorthernCloudywingButterfly.htm
- Identified as a Southern (bottom photo)—the face looks roughly as light as that of the HL cloudywing:
- www.carolinanature.com/butterflies/scloudywing.html
- Identified as a Northern (second photo)—the face looks much darker than that of the HL cloudywing:
- www.carolinanature.com/butterflies/ncloudywing.html
- Discussion and photos of Northern:
- zipcodezoo.com/Animals/T/Thorybes_pylades.asp
- Discussion and photos of Southern:
- zipcodezoo.com/Animals/T/Thorybes_bathyllus.asp
Identification?
Butterflying is still fairly new to me, and I have virtually no experience with the skippers—hence I have no intuitions to guide me. Based on what I’ve read in the three guides and on the internet photos, I’m leaning (somewhat tentatively) back toward Southern Cloudywing. Jim hasn’t yet seen the photo.
(There is a third possibility, which I’ve decided against: Confused Cloudywing. According to Heitzman, this is “very local and uncommon in southern and eastern Missouri”. Also, the descriptions of white spots in both Kaufman and Glassberg seem to rule out this species—both also mention the absence of white at the bend of the antennal club.)
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