Butterflies of
Mexico, USA & Canada
Gray
Hairstreak
Strymon melinus
H�BNER, 1813
Family - LYCAENIDAE
subfamily - THECLINAE
Tribe - EUMAEINI
Strymon
melinus, Indiana,
USA �
Chris Orpin
Introduction
Almost all neotropical and North American Theclinae species are
placed in the Eumaeini.
The tribe is not especially well represented in collections, so for
a long time many 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.
The genus Strymon comprises of 54 known
species, variously distributed across the Americas from Canada to
Chile and Uruguay. About 20 of these occur in North America.
The males of most species have metallic blue patches on the upper
hindwings, sometimes also on the forewings. Females of all species
have plain earthy brown uppersides. All species have a pair of short
'tails' at the tornus of the hindwing, although these are often lost
after the butterflies have flown for a couple of days. The
undersides vary considerably - e.g. in the
davara group of species they are marbled in shades of brown;
the acis group have pale brown
undersides with prominent white hairstreak lines and a large orange
patch near the tornus, and the basilides
group have pale undersides with a broken band of reddish spots.
Strymon melinus belongs to the
acis group. On the upperside both sexes
are dark earthy brown with a slight bluish or greenish sheen, and
have a conspicuous orange spot at the tornus. Males have a large
dark squarish patch of androconial scales at the end of the fw
discal cell.
The ventral ground
colour varies from silvery-grey to pale reddish-brown according to
subspecies. The white-edged black 'hairstreak' line is segmented in
all subspecies except clarionensis, in
which the line is contiguous, and edged inwardly with a broad red
band. The latter subspecies is currently under review and is likely
to be elevated to full specific status. In addition to
clarionensis there are 7 other subspecies -
setonia and
atrofasciata from Canada; melinus,
humuli and franki
from the USA; pudica which occurs from
Oregon and California to Nicaragua; and
caldasensis which is known only from Colombia. It's disjunct
distribution suggests that caldasensis
may in time be revealed to be another full species.
Strymon melinus is distributed from
Canada to Colombia.
Strymon
melinus male,
Great Blue Hill, Massachusetts, USA �
Frank Model
Habitats
This species is found in open flowery habitats at elevations between
sea-level and about 600m.
Lifecycle
The egg is white and dome-shaped. In Mexico and the USA it is laid
singly on the flowers or stems of the larval foodplants which
include Eriogonum ( Polygonaceae ),
Echinacea ( Asteraceae ) and
Acacia, Olneya and
Eysenhardtia ( Fabaceae ). The larva feeds on the flowerbuds,
petals and seeds of the plants. It is louse-shaped, with bristly
lappets below the spiracles. It exists in several colour morphs -
pale green yellowish-green or purplish, matching the colour of the
flowers or leaves of the various foodplants. In all varieties there
are suffused forward-slanting diagonal white bars on each segment.
Pupation takes place on the ground, and the pupa is quickly covered
in debris by ants.
Adult behaviour
The
butterflies are usually encountered in open sunny situations, perching
on the foliage of bushes, or nectaring at
Lantana, Senecio,
Rubus, Eupatorium,
Eriogonum and the flowers of numerous
other bushes and herbaceous plants.
Strymon
melinus female,
Arizona, USA �
Tony Hoare
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