Eastern Tailed Blue Butterfly Overview

An Eastern-tailed blue butterfly, also known as just Eastern-tailed-blue, is a butterfly that lives in North America and is unique for having tails on the tip of the hindwings.

Eastern Tailed Blue Butterfly Species Summary

Scientific NameCupido comyntas or Everes comyntas
Family NameLycaenidae
HabitatUndisturbed open spaces, alleyways, and pastures
RangeCentral and North America
Host PlantsFrogfruit, legumes, violets, clovers
Butterfly DescriptionDeep blue share with black or gray borders
Caterpillar DescriptionHairy thorax with dark brown stripes

What are the colors of the Eastern Tailed-Blue butterfly?

Both male and female Eastern-tailed blue butterflies have a deep blue shade surrounded by black borders (in males) or gray borders (in females) along the dorsal side of the costal areas. Small orange spots can be seen in both sexes but are more prominent in females.

The upper side of the males’ wings is iridescent blue, while the females’ dorsal sides are usually brown. As for the ventral side, both genders have pale gray base hues with numerous orange and black spots around the costal parts of the hindwings.

These butterflies, especially females, tend to change appearances in spring. Females are also relatively smaller than their male counterparts.

The ventral sides of their wings are pale blue or gray, with small black markings scattered throughout the surface. In some cases, orange spots (like those on the dorsal sides) can be found near the hairstreaks with hindwing “tails.”

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The Eastern tailed-blue is considered a gossamer-winged small butterfly. It has a wingspan that can barely reach an inch.

Eastern-Tailed Blue Butterfly
Eastern-Tailed Blue Butterfly

Caterpillar Physical Description

The Eastern tailed blue caterpillar has a small black head and dark green hairy thorax with dark brown stripes. Some larvae’s bodies come off as brown instead of green. Like their adult form, the caterpillars can only reach an inch upon maturity. The Eastern-tailed blue larvae can easily adapt to cold climates since they overwinter.

Where do Eastern Tailed-Blue butterflies live?

Undisturbed open spaces, alleyways, and pastures are the perfect habitats. Additionally, the Eastern tailed blue butterfly can be seen living and thriving in these spots:

  • Riparian areas
  • Natural lawns
  • Roadsides
  • Terrestrial spots
  • Meadows, both wet and dry
  • Sunny areas


There have been sightings of the Eastern tailed blue butterfly across Central and North America. It’s present in Canada as well as California and Oregon in the US. They have also been seen in the following counties in Alabama:

  • Autauga
  • Walker
  • Randolph

Host Plants

The female adult Eastern-tailed blue butterfly lays eggs on frogfruit, legumes, violets, and other host plants. Once the larvae emerge from their eggs, they crawl across the leaves and stems of the following food plants:

  • Downy milk pea (Galactia volubilis) and other pea-family plants
  • White clover (Trifolium repens)
  • Bush-clovers (Lespedeza)
  • Red xlover (Trifolium pratense)
  • Sweet clovers (Melilotus)
  • Tick-trefoils (Desmodium)

What do adult Eastern Tailed-Blue butterflies eat?

These adult butterflies get the nectar, flower buds, and seeds and sometimes eat the leaves of clovers, alfalfa, and vetch. They also like clover (Trifolium), wild pea (Lathyrus), wild strawberries, and the following food plants:

  • Asters
  • Shepherd’s needle
  • Winter cress
  • Cinquefoils
  • Bush clover (Lespedeza)
  • Flowers with short floral tubes

These butterflies play a significant role in pollinating various plants. However, they can’t feed from flowers with long tubes because they only have a short proboscis.

Why do these butterflies gather around mud?

Like other butterfly species, the males prefer to congregate and perform muddling or puddling. This process helps them get the necessary nutrients and moisture in preparation for the breeding season.

Behavior and flight

During the breeding season, the males will land on the food plants and wait for the females to pass by them. The females typically prefer young leaves or flower buds as their ideal sites for oviposition after breeding.

The Eastern-tailed blue butterfly has a weak and fluttery flight pattern and prefers to hover low–near the ground surface. Its wings stay partially open when it perches on plants and trees, and it displays the wings’ dorsal surface.

This species has about 3 broods annually, with the last one overwintering in bean and pea pods.

Do Eastern Tailed-Blue butterflies have any predators?

The Eastern-tailed blue butterflies caterpillars have many predators, such as:

  • Small mammals
  • Spiders
  • Wasps
  • Birds 

However, they have developed a good relationship with ants. The caterpillars secrete a compound some ant species like, so the ants protect them from possible threats.

What’s in the name?

Its name comes from the fact that it has an upward-pointing “tail,” similar to a bluebird’s. This is different from the tails of other butterfly species that only slightly protrude from the caudal parts of their hindwings.

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