Macrocneme thyra Moschler, 1883

Dietz, R.E. (1994). Systematics and biology of the genus Macrocneme Hubner
(Lepidoptera: Ctenuchidae). University of California Publications in
Entomology 113: pp. 60-66 (Figs. 54-57, 150-151, 190, 198, 215; Map 15).

Macrocneme thyra Moschler

Macrocneme thyra Moschler, 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 Moschler 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.

TYPE DATA. ! thyra Moschler: male holotype, interior of Surinam, MNHU.
! affinis Klages: female holotype, Suapure, Venezuela, Dec. 30, 1899, USNM
cat. no. 8414, USNM. ! chlorota Dognin: male holotype, Yuntas [=Juntas],
near Cali, Colombia, (Fassl), USNM. ! boliviana Draudt: male holotype, Rio
Songo [=R. Zongo], Bolivia, BMNH. ! intacta Draudt: male lectotype, here
designated, Trinidad, (Caracciolo), BMNH. ! albiventer Dognin: male
holotype, Nouveau Chantier, French Guiana, USNM.

GEOGRAPHICAL DISTRIBUTION. Widespread. Commonly encountered in Panama,
Venezuela, and Trinidad, in the Guianas, on Grenada, and on the
tributaries of the Upper Amazon in Ecuador, Peru, and Bolivia; scattered
records in Brazil include sites on the Amazon River and from the
southeast; the single record from Mexico is incongruous and not explained.

FLIGHT PERIOD. Collecting records show thyra to be active in every month
of the year.

REMARKS. To define thyra, I have overlooked the plasticity of the
phenotype and emphasized the non-varying structure of the male genitalia.
I have considered all specimens with a short juxta squared off below the
point of origin of the lower process of the valve to be thyra. Also, the
inner margin of the left clasper of the valve is distinctly emarginate
before the tip. By contrast, in the phenotypically similar and sympatric
lades, the juxta, although incised on the right, always extends beyond the
base of the lower process of the valve, and the emargination on the
clasper is absent, the edge smooth to the tip.

The sexes are dimorphic in the white markings and sometimes in the pattern
of wing iridescence. These differences are given under the description for
the female.

I have difficulty distinguishing between females of thyra and lades. The
caudal margin of sternite VII (Fig. 150) is variable. The mesal
emargination is sometimes absent. The internal genitalia are so similar
that positive identification is usually conjectural unless the sexes are
collected together and the males identified.

All the names synonymized under thyra represent geographic variants,
except albiventer which was applied to a specimen identical to the
Moschler holotype. The placement of affinis Klages in synonymy here is
questionable since the holotype is a female which I am unable to associate
with a known male. Its former synonymy with chrysitis Guerin is inaccurate
since chrysitis is restricted to Mexico and Guatemala. Also the hind tarsi
of chrysitis are black, whereas in affinis they are white-tipped. In the
original description Klages allied affinis with thyridia Hampson. The
affinis holotype is similar enough to thyridia to suggest that it is in
fact merely the unassociated female. On the other hand the color and
pattern of iridescence on the forewing and abdomen also closely resemble
thyra females from Guatopo National Park, Venezuela, where I have been
able to associate the sexes. Since I know of no other method for
distinguishing the females of these two species, I am emphasizing the
resemblance of the affinis holotype to thyra by the present synonymy.
Future biological information may alter this placement.

The name chlorota has been overlooked in the literature in reference to
Macrocneme due to its placement by Dognin in Calonotos. It is clearly a
Macrocneme and of the form of thyra from Colombia where the abdominal
underside is less white than the Guianan form.

The names boliviana and intacta refer to geographic forms of thyra from
Bolivia and Trinidad respectively. Their synonymy is discussed under
"Geographical Variation".

SPECIMENS EXAMINED (565): 349 males, 216 females. [Ecuador and Peru
entries only:] ECUADOR: Esmeraldas: Atacames; Imbabura: Paramba, BMNH (in
copula pair); Paramba, 3500 ft, BMNH; Rio Mira, Paramba, OX.
Santiago-Zamora: Macas, USNM. Ecuador, BMNH. PERU: Cajamarca: Rio
Tabaconas, 6000 ft, BMNH. Cuzco: Quincemil, 780 m, CNC. Huanuco: Cushi,
1900 m, BMNH; Palcazu, 235 m, BMNH. Junin: Chanchamayo, 1000-1500 m, BMNH;
Pueblo Pardo, Col[onia] de Perene, CU; Rio Perene. Lima: Lima, USNM.
Pasco: Oxapampa, CU. Puno: La Oroya [=Oroya], Rio Inambari, 3100 ft, BMNH;
La Union, Rio Huacamayo, 2000 ft, BMNH; Sto. Domingo, Carabaya, 6000 ft,
BMNH; Tinguri [Hacienda], Carabaya, 3400 ft, BMNH. San Martin: Tarapoto,
CU.