Macrocneme thyra Möschler, 1883

Möschler, H. B. (1883). Beiträge zur Schmetterlings-Fauna von Surinam. V.
(Supplement). Verhandlungen der kaiserlich-königlichen zoologisch-botanischen
Gesellschaft in Wien 32 (1882): p. 334, pl. XVIII, fig. 24 (as Macrocneme
Thyra n. sp.). Translated from the German original.

Palpi black, with a white edge. Fore coxae white, femora yellowish grey
outside, white inside, tibiae and tarsi black. Mid coxae and femora white, the
latter outside with a black longitudinal streak, tibiae black, streaked with
metallic green on the outer edge, tarsi black. Hind coxae and femora likewise,
tibiae black, with whitish streak-like scaling inside, with a faint metallic
lustre outside, tarsi black. Head black, frons with two white dots, collar
metallic green, in the middle with two fine white dots. Thorax metallic green.
Abdomen golden green, first segment black, with four white dots, in the middle
two small steel-green spots, venter white, edged with black at the tip. Wings
black, fore wings dusted with metallic green at the base and in rays in the
median area, most strongly at the costa and inner margin; at the base stand
two fine white dots. Hind wings uniformly black, white at the base on the
costa. Beneath, all wings dusted with steel green in the basal area, reaching
almost to the middle. 29.5 mm. One specimen from the interior.

Dietz, R. E. IV (1994). Systematics and biology of the genus Macrocneme Hübner
(Lepidoptera: Ctenuchidae). University of California Publications in
Entomology 113: pp. 60-63 (Figs. 54-57, 150-151, 190, 198, 215; Map 15).

Macrocneme thyra Möschler
Macrocneme thyra Möschler, 1883:334, pl. 18, fig. 24
Macrocneme affinis Klages, 1906:539.- Hampson, 1914:206 [as synonym of M.
chrysitis].- Draudt, 1917:204.- Zerny, 1931b:241 [NEW SYNONYMY]
Calonotos chlorota Dognin, 1914:Fasc. 7:8.- Hampson, 1914:215.- Draudt,
1917:205 [NEW SYNONYMY]
Macrocneme thyra boliviana Draudt, 1916:104 [NEW SYNONYMY]
Macrocneme thyra intacta Draudt, 1916:104.- Fleming, 1957:124.- Beebe &
Kenedy, 1957:151 (behavior) [NEW SYNONYMY]
Macrocneme albiventer Dognin, 1923:Fasc. 23:2.- Forbes, 1939:129 [synonymy].-
Fleming, 1957:124
Macrocneme chrysitis affinis.- Zerny, 1931a:13
Macrocneme thyra thyra.- Fleming, 1957:124

This is a widespread and extremely variable species, which accounts for much
of its synonymy. By distribution and variation M. thyra most closely parallels
lades, with which it is often sympatric. The two are easily confused, but
thyra can always be distinguished by the invariably whiter underside, the
juxta truncated below the lower processes of the valvae, and a spiculate
surface on the left spine of the aedeagus.

The following description is taken from a Guianan specimen (Wineperu, Guyana)
which closely resembles the Möschler type from Surinam. Because the phenotype
is variable, especially in color and pattern of the iridescence, not all
individuals will follow in detail.

MALE. Head: blackish brown; white spots below antennae large and approximate
on frons; white irrorations on vertex; labial palpi extending to base of
antennae, front of II white with scattered white on III. Thorax: disc
golden-green, margined along sutures with blackish brown hair-like scales;
metallic green spots on patagia large and laterad; metallic green streak
extending along fore and mesal margins of tegulae; underside of tegulae white,
but visible from above only along mesal margins; pectus mostly white, with
some blackish brown scales beneath wings and interspersed around coxae; legs
blackish brown; coxae and femoral grooves with opposing margins on fore and
mid tibiae white; inner mesal margins of fore and mid femora tan; hind tarsi
white-tipped. Forewing: ground color blackish brown, basal half metallic green
except along veins; small oblique black streak from basal angle; metallic
scales not reaching end of cell, appearing more concentrated below cell and
along inner margin; underside blackish brown with basal half metallic green;
white streak along A1 + A2, tan where wing overlaps, retinaculum white.
Hindwing: blackish brown with no iridescent scales; costal margin tan, with a
diffuse white spot basad; underside mostly metallic green except at outer
margin. Abdomen: metallic green, basal tergite black with metallic spot
between subdorsal white spots; underside entirely white. Genitalia: as in
Figs. 54-57 (drawn from RED prep. 39214, USNM, 18n); claspers of valvae
slightly asymmetrical, with left arm somewhat longer and more curved than
right arm, tip of left arm with dorsal edge more pronounced and emarginate
than corresponding edge on right tip; dorsum of uncus slightly convex, with
medial sulcus and lateral flanges; juxta truncate below ventral process of
valvae, small spot of spines in membrane at left; dorsum of aedeagus with two
strong spines of unequal length; left spine spiculate on ventral surface
except at tip.

FEMALE. Essentially identical to the male except: Head: white absent from II
and III of labial palpi. Thorax: white on underside restricted to small mesal
dots, making underside appear darker than in males; pectus blackish brown,
with white absent except as spot on pro and metapleuron; legs brownish black,
with white spots only on forecoxae, trochanters, and hind tarsi; tan scales
absent from mesal margin of fore and mid femora. Wings: ground color of wings
slightly darker, approaching brownish black; iridescent scales sometimes
sparse, blue-green instead of bright green; white streak absent along A1 + A2
on underside of forewing. Abdomen: white on abdomen restricted to medial row
of small spots and to subventral pair on basal sternite. Genitalia: as in
Figs. 150-151 (drawn from RED preps. 39213, USNM, and 39264, UCB; 13n);
sternite VII shield-shaped, with posterior margin irregular, notched mesad,
anterior margin with apex broad, skewed left, and two shallow, intersegmental
depressions on right, one separate and the other continuous from margin of
encircling pleurite; lamella antevaginalis with scattered longitudinal plicae;
sclerite of postvaginalis roughly oval, decurved at middle where ostium
originates; ductus bursae, corpus bursae, and stalk of accessory bursa with
concentric plicae; stalk of accessory comparatively short, with bursa not
extending beyond corpus bursae; signa of two opposing scallop-shaped patches
with recumbent spines.

INDIVIDUAL VARIATION. Length of forewing: male, 15.8-18.2 mm; female,
15.8-18.0 mm. In all the descriptions of thyra or of one of its forms, the
ground color of the wings and thorax is given as black. The color is actually
brownish black, with certain populations, especially from the Guianas and
eastern Venezuela, having a distinctly browner hue. This may in part be due to
age, but fresh specimens as well as those in old collections can accurately be
predicted as originating from these areas without reference to their
collection labels. Individuals from any one locality normally have the same
ground color, and the sexes are identical.

The only truly black scales on the wings form a streak at the base of the
forewing. They are present either in a horizontal streak below the cell or as
an oblique streak extending through the cell to the costa, or they are absent.
Both M. intacta and boliviana were distinguished as subspecies partly on the
basis of the forewings lacking these black scales, which made the iridescence
appear entire. An examination of a series of specimens from localities as far
apart as Trinidad and Bolivia shows that black scales are normally present and
interrupt the iridescence except in a few specimens. The character is highly
variable, and its absence in individuals is within the usual range of
variation found in Macrocneme. Little taxonomic value should be attached to
it.

The color of the wing iridescence is usually consistent within a population,
but may vary between populations from golden-green, to green, to blue-green,
to deep blue. Where metallic scales extend to the termen in the forewing (=
boliviana), the color varies from dull blue to blue-green in the specimens
from Bolivia, while specimens from Tabaconas (Peru) are bright green, and
those from Guatopo National Park (Venezuela) dark blue. Sometimes, within a
single population, combinations of colors occur, as in three specimens with
similar data from Simla, Arima Valley, Trinidad. In one both wings are green,
in a second they are blue, and in the third the forewing is green and the
hindwing blue.

GEOGRAPHICAL VARIATION. Although most species of Macrocneme show some form of
geographical variation, in thyra the problem is complicated by a very wide
distribution that has numerous geographic components, each appearing slightly
different. The geographic limits for these are not always clear, since
individuals even within a colony vary. Invariably the ranges overlap. Possible
combinations in independently varying characters are so numerous that any
attempt to describe forms is meaningless. Nevertheless some trends exist, and
a few local populations are consistent enough to be recognized geographically.
The typical Guianan form of thyra, as represented by the male holotype from
Surinam, or albiventer Dognin from French Guiana, is wholly white on the
pectus and venter, and the forewing underside is streaked with white on the
inner margin. In other parts of the range, the venter is usually less white,
especially toward the apex. Occasional specimens from widely disjunct
populations (Para or Mirapinima, Brazil; Quincemil, Peru; or Macas, Ecuador)
may be as white as the Guiana form or even whiter (Perene, Peru; Port of
Spain, Trinidad) if the inner margin on the forewing and the hindwing costa
become extensively white basally. The usual pattern is for the three basal
abdominal segments to be entirely white and the remaining segments to vary
from mostly white to having a series of small mesal dots. Specimens that are
profusely white on the underside (cf. Perene and Trinidad) tend also to be
more extensively white on the legs and labial palpi.

The amount of white on the wing underside can vary considerably among
individuals from one geographic area. In Trinidad a specimen from Port of
Spain is extensively white at the inner margin of the forewing and at the
hindwing base, while a specimen from Simla shows almost no white in these
areas. Hampson (1898) considered the latter variant to be a subspecies of
thyra, and Draudt (1916) named it intacta. I see no evidence of geographic
isolation in this character. Similar variation is also found in mainland forms
from the Guianas to Peru. The genitalia in all forms are essentially
identical.

The most prevalent interpopulational variation in thyra occurs in color and
pattern of iridescence. The usual pattern on the forewing is for the basal
half to be covered with metallic green scales which do not extend beyond the
discocellular, and a variable black streak extending distad from the basal
angle. The iridescence may be uninterrupted, but generally the veins appear as
thin dark lines. In some specimens the iridescence is reduced to a basal spot
and a streak along the inner margin. In others the distal margin of the
iridescence is lost in a general metallic suffusion extending beyond the cell
towards the termen. The color is usually blue or blue-green. Hampson (1898)
considered this variant distinct enough to be a subspecies, and Draudt (1916)
subsequently named it boliviana. As the name suggests, the form commonly
occurs in Bolivia (Coroico; Rio Zongo), but it is not restricted to this area,
occurring also in Peru (Tabaconas) and Venezuela (Guatopo National Park; Rio
Morichal Largo). A difference in the Venezuelan populations is that the
suffusion is found only among females. This dimorphism is weak and possibly an
artifact of the small sample size, since other females in the same population
appear identical to the males.

Most examples of thyra have a patch of metallic scales in the discal area of
the hindwings, but in specimens from the Guianas and eastern Venezuela this
iridescence is absent, or occasionally present only as a few scattered scales.
In one specimen from El Dorado (Venezuela), the hindwings are fully
iridescent, while among specimens from Maracay (Venezuela) the metallic patch
is either present or absent on the hindwing. Specimens from Panama (Chiriqui;
Rovira) and Costa Rica show no iridescence in the hindwing, yet the
populations in Mexico (Veracruz) clearly possess it.

None of the authors who named forms of thyra mention the iridescent striae on
the abdomen. These are present in numerous specimens. The dorsum can be either
iridescent green or have the metallic scales restricted to three longitudinal
striae. There are two sublateral lines extending the length of the abdomen
which are broader than the thin mid-dorsal line that may obsolesce beyond the
middle. In the females the abdominal iridescence is often duller and darker
than in males, making the striae appear faint or absent. These striae are
particularly notable in the Trinidad populations (= intacta) and in
individuals from the Guianas and Venezuela. The Andean, Central American, and
Mexican populations are usually entirely iridescent with the striae not
evident.

Besides boliviana and intacta, there is a form from Ecuador (Paramba;
Atacames) and Colombia (Rio Dagua; Medellin) in which the distal margin of the
forewing iridescence is sharply delineated and bright green. It closely
resembles examples of semiviridis from the same localities and could be
confused, except that its hind tarsi are white-tipped. Other specimens from
Colombia, although showing the same sharp delineation in the forewing
iridescence, may be blue-green (Santa Cecilia), or the male may be blue and
the female green (Alban).

Where thyra occurs sympatrically with lades, the two species share similar
patterns in variation. Both are browner in ground color in the Orinoco and
Guiana drainages than in other parts of their range. In the Guianas and
eastern Venezuela, where thyra is heavily white on the underside, lades has
the white on the venter attenuating caudally. In western Venezuela, Costa
Rica, and Mexico, where thyra is white at the base of the venter and has mesal
spots caudally, lades is always less white and usually only has a mesal series
of spots. Sometimes the venters appear identical in these species, but thyra
males can always be distinguished by the white scales on the palpi and on the
inner margin of the forewing underside.