Moths of North Carolina
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Sphinx Members:
8 NC Records

Sphinx franckii Neumoegen, 1893 - Franck's Sphinx

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Superfamily: Bombycoidea Family: SphingidaeSubfamily: SphinginaeTribe: SphinginiP3 Number: 890117.00 MONA Number: 7808.00
Comments: This large genus of some 27 species ranges from England to Japan and down through the Americas. There are approximately 14 resident species in North America and at least 5 in North Carolina. Two very different larval types occur in the genus and it is likely that Sphinx is composed of more than one genus.
Species Status: Barcodes indicate that Sphinx franckii is a single, well-defined species in our area.
Field Guide Descriptions: Covell (1984)Online Photographs: BugGuide, MPG, BAMONATechnical Description, Adults: Forbes (1948); Hodges (1971); Tuttle (2007)Technical Description, Immature Stages: Forbes (1948); Tuttle (2007)                                                                                 
Adult Markings: A large gray sphinx moth with yellowish-tan shading, particularly along the inner margin; its size and its coloration distinguish this species from other sphingids in our area. Sexes are similar.
Wingspan: 10 - 12.8 cm
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: Larvae are pea-green with two sub-dorsal lines that are green on the upper side and yellowish white on the lower; the usual pale lateral oblique lines are crossed by a pale lateral stripe (see Forbes, 1948, for more details). Pupation occurs underground.
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Potentially statewide but our records are too poor to demonstrate its true distribution.
County Map: Clicking on a county returns the records for the species in that county.
Flight Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge
Flight Comments: In the Coastal Plain look for adults on the wing from the last week in May through the first or second week of June, perhaps a week later in the Piedmont.
Habitats and Life History
Habitats: A woodland species found where ash is common, usually in basic-mesic hardwood forests in the uplands and rich, alluvial bottomlands. The recent observation of this species along the coast indicates that it might also use species of Ash that occur in blackwater swamps, i.e., Carolina Ash and Pumpkin Ash.
Larval Host Plants: Stenophagous, probably feeding primarily or even exclusively on Ash. Forbes (1948) states that Elm is used, but Tuttle (2007) notes that no source for the information was given and that captive larvae refuse to feed on elm. The few larvae that have been found in the field were feeding on Ash, including a mature larva discovered by Sullivan in McDowell Park (Mecklenburg Co.) feeding on a small waist-high ash in August. Any use of Elm needs to be confirmed and is currently discounted.
Observation Methods: Adults come to lights but apparently do not visit flowers or baits. High intensity UV lights, such as mercury-vapor, may be needed to more effectively sample for this species. Caterpillars should be searched for in July and early August. Sleeve them on the foodplant which wilts badly when cut.
See also Habitat Account for General Ash Forests
Status in North Carolina
Natural Heritage Program Status: W3
Natural Heritage Program Ranks: G4 SU
State Protection: Currently placed on the Watch List by the North Carolina Natural Heritage Program. However, it has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: Long thought to be one of the rarest sphinx moths in eastern North America, it is now known to have a short flight period during which in the right habitat it is not uncommon. However, as an ash-feeding species, it appears to be under severe threat due to the spread of the Emerald Ash Borer, an exotic beetle that threatens to destroy most species of Ash in eastern North America (see Wagner, 2007, for a discussion of the threat posed to ash-feeding Lepidoptera due to the invasion by this exotic pest).

 Photo Gallery for Sphinx franckii - Franck's Sphinx

Photos: 7

Recorded by: Darryl Willis on 2021-05-28
Cabarrus Co.
Recorded by: Parker Backstrom on 2015-08-06
Chatham Co.
Recorded by: Parker Backstrom on 2015-08-06
Chatham Co.
Recorded by: Z. Taylor Piephoff on 2012-05-31
Brunswick Co.
Comment: Photographed at outdoor lights at a tennis court
Recorded by: Darryl Willis on 2010-08-15
Cabarrus Co.
Recorded by: (Collector's name on label is illegible) on 1963-06-27
Wake Co.
Comment: Specimen in NCSU Insect Museum. Originally identified as Sphinx chersis but now determined to be S. franckii. Wingspan = 11.1 cm; forewing length = 5.1 cm
Recorded by: Collector not given on the label but probably C.S. Brimley on 1912-06-09
Wake Co.
Comment: Specimen in NCSU Insect Museum. Originally identified as Sphinx chersis but now determined to be S. franckii. Wingspan = 11.1 cm; forewing length = 5.2 cm