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This tribal concept embraces all of the Geometrinae except the
Dysphaniini. Therefore any groupings recognised within it will have subtribal
status (names ending in -iti: the alternative suffix -ina is used at a higher
level in the Lepidoptera, e.g. Heterobathmiina, Neopseustina; see also Nässig
(1995) for use of -iti). Before assessing the validity of such groupings
proposed in recent literature (e.g. by Inoue (1961) and Ferguson (1969)) and the relationship between New World and Oriental
concepts (see also Pitkin (in press)), the characters that may serve to define
the tribe as a whole will be discussed. Most of these are widely distributed
over the group but are not necessarily well developed in all taxa. Nevertheless,
they might be considered to be geometrine ground-plan features.
There are perhaps seven such characters. In addition, the cruciform
vinculum feature mentioned above as a possible synapomorphy for Dysphaniini and
Geometrini sees its greatest development in some genera of Geometrini, e.g. in
Figs 123, 151, 172, 202, 233, 279, 284, 344, 361 and 378.
Green colouration. This feature is widespread throughout the group except in the more
robust Pseudoterpniti genera, though even these include a number of taxa where
green is extensive, e.g. Herochroma Prout and Actenochroma Warren.
Reduction of the frenulum. This character was noted by Prout (1912a) and
Ferguson (1985) as a feature partially diagnostic for Geometrinae: the frenulum
is reduced in size or absent. This is associated with expansion of the humeral
area of the hindwing that becomes more angled at the position of the frenulum
base (e.g. Fig 3). This character is variable throughout the group, relatively
weakly developed in most Pseudoterpniti but strongly so in the Hemitheiti.
Paired setal patches on male sternite 3.
Setal patches on sternite 3 are present generally throughout the Geometrini
though they are absent from a scattering of genera (e.g. Ornithospila Warren).
In most cases they are small, widely separated (Figs 241-243), and not elongate
as in the Desmobathrini. In a few genera (e.g. Jodis Hübner, Berta Walker)
they are more generally dispersed sparsely over a central circular area (Figs
384, 399), but modification of this type occurs sporadically and rarely in a
number of generic groupings and probably represents a derived state of the
ground-plan pair of setal patches. It is not clear whether this character is
homologous or homoplasious with the condition in the Desmobathrini. Setae on
this segment are usually associated with the presence of a hair pencil sheathed
in the hind tibia (Holloway, 1993 [4]: 11), and this may prove to be a
synapomorphy grouping together the Desmobathrinae, Geometrinae and Ennominae
(where the setae occur in a transverse comb).
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Socii of male genitalia well developed often with parallel reduction of
uncus. Setose
socii arising from the junction between the base of the uncus and the bases of
each side of the gnathus, are moderate to strong in all Geometrini, but
vestigial in the Dysphaniini. However, the development varies from the level
seen in some Ennominae tribes and the Eumeleini, e.g. in the Nemoriiti and
Rhomboristiti, where the uncus is relatively strong, through the condition in
the Hemitheiti where they usually equal the uncus in length and are closely
adpressed to it, to that in the Pseudoterpniti, Geometriti and Comibaeniti where
the uncus is vestigial and the socii predominant.
Aedeagus with sclerotisation reduced to a ventral strip along length. The
aedeagus is usually differentially sclerotised more strongly ventrally, a
feature also seen moderately in the Dysphaniini, but only weakly developed, if
at all, in a few Geometrini groups, such as the Pseudopterpniti (Epipristis Meyrick
is an exception). Prout (1912a) described this condition as pestillate
(pestle-shaped). The aedeagus vesica usually lacks significant cornuti,
exceptions being Pingasa Moore and Metallolophia Warren in the
Pseudoterpniti, Spaniocentra Prout in the Rhomboristiti, Chlorissa Stephens
in the Hemitheiti, and the genera Dooabia Warren and Paramaxates Warren.
In the majority of genera showing this feature of ventral sclerotisation
the insertion of the ductus ejaculatorius tends to be more placed to one third
to half way towards the apex of the aedeagus.
Oblique, papillate ovipositor lobes. The distal margin of the ovipositor lobes
recedes obliquely ventrally, with the setae set irregularly on papillate
projections (see Figs 157, 225, 291, 323 and 386). This appears to be one of the
most clearly definitive features of the Geometrini and is widely distributed
over the included genera. It is absent in only a few instances, notably in the
Geometriti, but also in the possibly allied Timandromorphiti and the genus Paramaxates:
in these groups the lobes are somewhat semicircular and normally setose. In
the Neohipparchiti the ovipositor lobes are sclerotised, acute.
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Bicornute signum. When a signum occurs in the bursa copulatrix, it generally consists of
two small spines on a sclerotised pad (e.g. Figs 162, 215, 274 and 314). This is
modified in some taxa into a more irregular, transverse ridge or less well
defined sclerotisation, e.g. in some Nemoriiti (Pitkin, 1993). The bicornute
state is also present in Pseudoterpniti, Geometriti, and the majority of
Hemitheiti, though is modified to a disc or ring in Aporandria Warren and
Oenospila Swinhoe. The principal exception noted in the Bornean fauna is Ornithospila
Warren where the signum is an ovate patch of scobination.
The two female characters, together with green colouration, appear to
provide the best definitive features for the tribe.
Salkeld (1983) noted that the eggs of geometrines were mostly of a
flattened, pill-box shaped type, but that this shape was not unique to the
subfamily. The larvae often have a strongly granular skin, not seen in
Dysphaniini.
Features that may be useful to group genera into subtribes include the
degree of development of the socii versus the uncus, pectination of the male
antennae, facies characters, such as for the Pseudoterpniti, and characters of
the venation of the hindwing. In the Hemitheiti veins M3 and CuA1 usually share
a common stalk. In Nemoriiti this feature is sometimes present (Pitkin, 1993),
more constantly so in Indo-Australian representatives (e.g. Fig 3). In other
groups these veins are connate or separate.
There follows a preliminary attempt to define groupings of genera in the
Oriental fauna and to relate these to New World groupings (e.g. in
Ferguson (1969) and Pitkin (in press)). However, the classification is
not sufficiently clear to merit formal subtribal headings in the account of the
Bornean fauna following.
Some reference is also made to the findings of Stekolnikov &
Kuznetsov (1981), studying male genital morphology of a small selection of
Palaearctic genera.
Pseudoterpniti (= Archaeobalbiti, and Terpnini sensu Inoue (1961)). This name probably
embraces all the relatively large, robust Indo-Australian genera where the
facies
consists of a more mottled forewing ground, with strong, crenulate fasciae: a
rather boarmiine-like facies. On the underside there are strong black discal
dots and broad black bands towards the margin in most taxa, though not the type
genus, the Palaearctic Pseudoterpna Hübner. In the hindwing the frenulum
is moderate and the humeral zone not particularly expanded. The male antennae
are filiform, ciliate, serrate or (as in the type genus) rather narrowly and
densely bipectinate, the pectinations tapering away to a point between two
thirds and four fifths of the way to the apex. Veins M3 and CuA1 of the hindwing
are usually separate.
In the male genitalia the aedeagus is usually tubular, not more strongly
sclerotised ventrally. Coremata are usually present on the valves.
Interpretation of the condition of uncus and socii is difficult. Either the
socii have become fused to the basal plate of the uncus, with the distal part of
the latter reduced or absent, the socii themselves becoming massive, even fused
to give what appears to be a bifid uncus in genera such as Pingasa and Dindica
Moore, or the socii are vestigial to absent, with the uncus becoming
increasingly divided, the processes becoming well separated, often massive. In Actenochroma,
a central digitate feature may represent the uncus and would lend support to
the first alternative: usurpation of the function of the uncus by the socii,
with convergence and fusion of the latter in some taxa. Herochroma, with
a weak, bibbed uncus, represents an intermediate condition. A transformation
series along these lines is represented by the following sequence of genera in
the group occurring in Borneo: Orthorisma Prout (socii small relative to
massively bilobed uncus), Actenochroma, Herochroma, Sundadoxa Gen. n., Pullichroma
Gen. n., Metallolophia Warren, Epipristis, Pingasa, Pachyodes Guenée,
Lophophelma Prout, Dindica. The tribal type genus has the socii/uncus
structure much as in Epipristis.
In the female genitalia, both ovipositor lobes and signum (when present,
e.g. in Herochroma) are typical of the Geometrini.
Geometriti. This, the nominate subtribe, consists also of robust taxa with a bifid
uncal structure that is either homologous or homoplasious with the situation in
the Pseudopterpniti. The two groups are distinguished by facies and the
condition of the ovipositor lobes. The facies of Geometriti is a uniform, clear
green, with paler rather than darker, fasciation on the upperside and no strong
black marking on the underside. The ovipositor lobes are atypical, lacking the
diagnostic Geometrini form described above, resembling more the typical geometrid
condition. The signum is bicornute. The condition of the ovipositor lobes may
represent a reversal.
The forewings are often
falcate, particularly in the two Bornean genera of the group, Tanaorhinus Butler
and Mixochlora Warren, but only (and much more weakly) in a few species
of the typical genus Geometra Linnaeus.
The male antennae are
narrowly bipectinate, and veins M3 and CuA1 are separate in the hindwing.
The larvae of the type
genus are characterised by paired conical processes occurring dorsally, directed
forwards, on segments A1-5 and A8.
Groups that may be
related to Geometriti include the Timandromorphiti, Neohipparchiti and Aracimiti.
Timandromorphiti. This subtribe consists only of the type genus, Timandromorpha Inoue.
This has a prominently bifalcate forewing and rather distinctive facies.
Venation of the hindwing is as in Geometriti, and the male antennae are
moderately bipectinate. In the male genitalia the socii and uncus are equally
developed; the valves are invested with an irregular array of short, robust
setae, and the aedeagus is slender, tubular. The eighth segment of the male
abdomen is modified, sclerotised, a feature also seen in Aracimiti. The female
genitalia have the ovipositor lobes intermediate between the characteristic
geometrine type and the unmodified condition of the Geometriti.
Neohipparchiti. Neohipparchus Inoue has venation as in the Geometriti and
somewhat similar facies. In the male genitalia the uncus has a slender, rodlike
distal portion flanked by robust socii. In Chloroglyphica Warren,
represented in Borneo, the socii can be separated by a rather broad, U-shaped
basal portion of the uncus: in this the genus shows some resemblance to Actenochroma
of the Pseudoterpniti. In both genera the male eighth sternite is variously
modified and the aedeagus sometimes has a lateral spur. The male antennae are
narrowly bipectinate.
The female genitalia
have the ovipositor modified into an acute, slender, conical structure with a
sparsely setose, smooth surface, possibly a modification of the Geometriti
condition. The bursa copulatrix is large, narrowly elliptical, slightly fluted
and more sclerotised and finely scobinate basally: there is no signum.
Aracimiti. The eastern Palaearctic genus Aracima Butler bears a loose
external resemblance to a number of Bornean taxa such as Paramaxates Warren,
Dooabia Warren, Euxena Warren and Chlorodontopera Warren. Aracima
itself has a remarkably expanded male eighth segment with broad, lateral,
hook-like flaps, and the uncal structure consists primarily of the socii
modified as robust, clawed plates. The ovipositor lobes of the female are of the
modified geometrine form. Setal patches are present on the male third sternite,
and the male antennae are narrowly, robustly bipectinate.
Dooabia has the uncus reduced to socii much as in Pseudoterpna, and
the male eighth segment is slightly modified. The female has modified geometrine ovipositor lobes and a bicornute signum. In Paramaxates
the eighth segment of the male is massively developed. The socii are strong,
slender, curved, digitate, separated by a small plate representing the uncus. In
the female the ovipositor lobes approach the Geometriti condition: there is a
bicornate signum. The male antennae of both genera are filiform, lacking cilia.
Euxena and Chlorodontopera resemble each other in facies. In the males Chlorodontopera
has the eighth segment weakly modified, whereas in Euxena it is
barely so. Uncus and socii are strong in both genera, the former slender in Euxena,
broad in Chlorodontopera. The ovipositor lobes of both are of the
modified geometrine form. The signum is a transverse flange in Euxena, but
is absent in Chlorodontopera. The male antennae in Euxena are
filiform, but in Chlorodontopera they are narrowly bipectinate.
These four genera are perhaps best placed in the vicinity of Geometriti
and allied groups on the strength of the development of their socii relative to
the uncus, rather robust character and general facies. The venation of the
hindwing is also consistent with this placement, CuA1 and M3 arising separately
from the cell in all except Euxena where they share a common stalk.
Agathia Guenée. This diverse Old World genus does not fit easily within any
currently recognised tribal grouping, but it would be unwise to erect a new one
until the classification of the Geometrini as a whole is better understood. The
uncal structure resembles that of Pseudoterpna and Dooabia in
apparently consisting of the two socii closely adpressed, fused over their basal
half, with the uncus itself vestigial, reduced to a plate between the base of
the socii. In the female the ovipositor lobes are of the modified geometrine
type, with the signum typically bicornate. The valves of the male are
distinctively ornamented. The setae on the third sternite are well developed.
The facies is also striking and diagnostic, and the male antennae are filiform,
lacking cilia. In the hindwing, veins CuA1 and M3 are connate at the cell.
Stekolnikov & Kuznetsov (1981) suggested the genus could be placed in the
Ochrognesiini (see Nemoriiti below).
Ornithospila Warren. This genus is set apart from the rest of the Geometrini by the
condition of the female signum: elongate, ovate, scobinate. The ovipositor lobes
are of the modified geometrine type however. The hindwing venation is as in the
groups already discussed. The male antennae are bipectinate to three-quarters,
the pectinations narrow, neat and numerous. The green of the wings is bright as
in Agathia rather than more emerald as in most other groups.
The male abdomen lacks setal patches on sternite 3. The vinculum lacks
the strongly cruciform state seen in many Geometrinae, and there is development
of a slight saccus. The socii are slender, closely adpressed to the uncus as in
the Hemitheiti, but unusually doubled (an additional smaller outer process) in
the typical subgenus.
Nemoriiti. The New World tribe Nemoriini recognised by Ferguson (1969) and
reviewed by Pitkin (1993, in press) is represented in the Indo-Australian tropics by the Ochrognesiini of Inoue (1961). The New World
name has priority. The tribe can be defined principally on features of the male
abdomen: a central longitudinal thickening and sclerotisation of the eighth
sternite that bifurcates along the anterior margin that is usually concave or
obtusely cleft, and broadens posteriorly around a cleft, often between a pair of
lobes, or acute processes; a similar but shorter sclerotisation of the anterior
margin and lobing of the posterior margin of the eighth tergite; an elongate,
often apically spatulate or even bilobed uncus, set between moderate to well
developed, often divergent socii; sclerotisation of the valve costa, often
modified or produced into processes along its length from base to apex. The
modification of the eighth sternite is the most consistently present of these
features.
The saccus is sometimes bilobed, the vinculum tending towards the
Comibaeniti condition. Coremata are present at the base of the valves.
The venation of the hindwing has the condition of veins M3 and CuA1
relative to the cell variable, ranging from separated to sharing a common stalk.
The antennae of the male are usually bipectinate in Neotropical taxa (Pitkin,
1993) and more variable in Indo-Australian ones, with ciliate and serrate states
evident as well as the pectinate one.
Rhomboristiti. The two Indo-Australian genera grouped under this name, Rhomborista Warren
and Spaniocentra Prout, and a new one described on (Rhombocentra
Gen.n), share two
particular features of the male genitalia: a strong uncus with only weak socii
(perhaps a plesiomorphic feature or a reversal), but with a similarly strong
gnathus; a prominent harpe-like process, often double, in the centre of the
valve. There are no coremata on the valve. The facies has irregular marginal
blotches of a type only otherwise seen in the Comibaeniti amongst the
Indo-Australian fauna. The genitalic features are also seen in the New World Lophochoristiti,
though the socii are moderate, and also the western Palaearctic Heliotheiti.
The name Rhomboristiti has priority. The male antennae are bipectinate, and
setal patches are present on the third sternite. M3 and CuA1 are separate or
connate on the hindwing. The ovipositor lobes of the female are of the modified
geometrine type, but no signum has been observed in the bursa of the taxa
dissected.
Comibaeniti. This group is again defined on genitalic features. In facies many taxa
resemble some Spaniocentra species. The most distinctive genitalic
feature is the vinculum which has become a narrow sclerotisation that is broadly
square or triangular with a shallowly concave zone between the angles. In the
extreme situation of Comostolodes Warren, the two angles have converged
to give an acutely bifid effect, and the sclerotisation of the eighth sternite
shows parallels with the definitive state for Nemoriiti.
The socii are prominent, as much or more so than the uncus which is
bifid in most cases, vestigial to absent in Comostolodes and Protuliocnemis
Gen. n.. Valve ornamentation when present is costal, often a massive
spur.
The male antennae are strongly bipectinate. Veins M3 and CuA1 in the
hindwing are separate or connate. The ovipositor lobes are of the
modified geometrine type, though this feature is not marked. The signum,
when present, is bicornute or a ridge.
The larva has the habit of attaching debris to itself (McFarland, 1988;
see also illustrations in Sugi (1987)). This feature is also observed in the New
World Synchloriti (Ferguson, 1969; McFarland, 1988; Pitkin, in press),
where similar characteristics of the uncus and socii occur, but a more typical
cruciform condition is seen in the vinculum. The groups are probably related.
The name Comibaeniti has priority.
Stekolnikov & Kuznetsov (1981) separated this group from the rest of
the Geometrini on the basis of their study of male genital morphology, but
characters of the male eighth sternite and of the flanged larva suggest a
relationship to the Nemoriiti.
Bornean genera included are Comibaena Hübner, Argyrocosma Turner,
Comostolodes and Protuliocnemis. The Palaearctic genus Thetidia
Boisduval also belongs to the group.
Hemitheiti. This subtribe embraces the majority of the Geometrini, particularly the
more bluish or emerald green taxa. A number of possibly apomorphic features are
found widely in the group, though not necessarily in every genus.
The socii and uncus are more or less equivalent in size, the former
never less than half the length of the latter and usually closely adpressed with
it. Veins M3 and CuA1 of the hindwing are usually stalked. The greatest
reduction and frequency of loss of the frenulum also occur in this group. The
male antennae are often strongly bipectinate, the pectinations long, untidily
adpressed to the shaft, though this feature is not seen in Neotropical
representatives (Pitkin, in press). Larvae are usually slender, the head capsule
often distinctly cleft or bifid dorsally; the resting posture is stick-like.
Female genitalic features are typical of the Geometrini, though there
are a few instances where the stucture of the signum is modified.
The concept of Hemitheiti recognised here embraces several other names
listed in the section on family-group names: Thalerini (= Chlorochromini),
Comostolini, Hemistolini, Jodini, Thalassodini. No clear indications of further
subgroups have been detected, though a few generic groupings are noted in the
main text following.
Genera included in Hemitheiti here are those from Aporandria Warren
to Comostola Meyrick.
A few subtribes are not represented in Borneo. The Dichordophoriti
were proposed by Ferguson (1969) to include a small number of New World taxa.
The male genitalia have uncus and socii reminiscent of the Comibaeniti and
Synchloriti, but the valve is unusual with strong ventral modification and also
coremata, and the saccus is narrow, well developed, conical.
In addition, there are a few Bornean genera that do not fall readily
into any of the categories above. These are treated at the end, commencing with Mystichlora
Gen. n.
The Geometrini as a whole have larvae that are predominantly tree-or shrub-feeding and would be expected to be more diverse in forested or
wooded ecosystems, as is in fact the case.
Within this arboreal feeding preference there are several groups where
feeding on the reproductive parts of the host, or at least the young foliage, is
common or prevalent: Nemoriiti, Comibaeniti, Hemitheiti, and to some extent the
Pseudoterpniti.
The adults appear to fly particularly in and above the canopy in Bornean
rain forest (Holloway, 1984a).
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