Butterflies of the
Amazon and Andes
Family - LYCAENIDAE
subfamily - THECLINAE
Tribe - EUMAEINI
Tingo Maria, Peru
© Peter Maddison
Almost all neotropical Theclinae species are placed in the Eumaeini.
The tribe is not particularly well represented in collections, so
until fairly recently a high percentage remained unstudied, and were
inappropriately filed away in the 'convenience' genus
Thecla. Many taxonomists have attempted
to rationalise the systematics of the Eumaeini, the most recent
being Robbins who published a revision in 2004, reclassifying the
taxa into 83 genera. Currently there are 1058 known species. Taking
into account their small size, secretive behaviour, and the great
similarities between many species, it is estimated that about
another 200 species probably remain to be discovered.
are 9 Arcas species, found variously
from Mexico to Bolivia and Argentina. All have metallic green
undersides, frosted or peppered with black, and on most species
there is a broad black band across the hindwing. All
Arcas species have a pair of long
twisted filamentous tails on the hindwings. On the upper surface the
males are metallic turquoise, green or blue according to species,
and have a broad suffused area of dark brown around the apex and
wing margins. Females are usually more bluish on the upperside, and
have a more rounded apex to the forewings.
Arcas tuneta is found on the Guyana
Shield and on the eastern slopes of the Andes from Colombia to
Bolivia. It also occurs in western Brazil.
This species is found in rainforest and transitional cloudforest
habitats at elevations between about 200-900m.
To be completed.
sexes probably spend most of their lives in the canopy, however they
have a strange tendency to suddenly appear 'out of nowhere', dropping
from trees to settle on the leaves of saplings in dappled sunlight. At
such times the hindwings of males are gyrated, drawing attention to
the long filamentous tails. Females have a greater tendency to lie
flat against a leaf, and do not normally gyrate their tails, although
the slightest breeze is enough to make them wiggle and attract