Eastern Tailed-Blue
Cupido comyntas
Last reviewed: June 2026
Eastern Tailed-Blue is known for its tiny tail-like extensions on hindwings.
Host plants
Eastern Tailed-Blue caterpillars can only develop on their larval host plants. Plant one of these natives and you can host the full life cycle in your own yard (host plant associations per the Xerces Society (opens in new tab)).
- Trifolium repens — see Tomcat Clover (same genus)
- Medicago lupulina — see Little Bur-clover (same genus)
- Common Bird's-foot Trefoil (Lotus corniculatus)
- Yellow Sweetclover (Melilotus officinalis)
- Showy Tick Trefoil (Desmodium canadense)
Want Eastern Tailed-Blue in your yard? Open Common Bird's-foot Trefoil in Pollinator Patch and plan an HOA-friendly garden around it for your region.
Family
Lycaenidae
Wingspan
18–25 mm
Active
May through September
Range
WI, AL, AR, DC and 36 more states
How to identify it
Look for tiny 'tails' on hindwings and small blue to grayish coloration; males and females have distinctly different appearances.
Good to know
- Males have distinctive small tails on hindwings that help distinguish them from other small blue butterflies
- Larvae have a symbiotic relationship with certain ant species
- Females can vary in color from blue to brown for camouflage
Common questions
- What do Eastern Tailed-Blue caterpillars eat?
- Eastern Tailed-Blue caterpillars feed on Trifolium repens, Medicago lupulina, Lotus corniculatus, Melilotus officinalis, and Desmodium canadense. These are the larval host plants the caterpillars must have to develop, per the Xerces Society and host plant records compiled from GBIF and iNaturalist.
- Where do Eastern Tailed-Blue live?
- Eastern Tailed-Blue is found across WI, AL, AR, DC and 36 more states.
- When are Eastern Tailed-Blue active?
- Adult Eastern Tailed-Blue are typically on the wing from May through September.
Range and life-history data compiled from iNaturalist, GBIF, and the Xerces Society. Photo licensed cc-by-nc.