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The
genera following share with each other and with the New World Metalectra
Hübner
a similar but somewhat unusual structure of the male eighth sternite and, where
known, larvae that feed on bracket fungus. There are also similarities in facies:
many Metalectra
species
resemble the Bornean Drepanorhina shelfordi Swinhoe, though this has a somewhat
modified male eighth sternite with lateral rods. Typically, this sternite is
shallow, but broad, the anterior margin narrowly thickened, W-shaped or somewhat
trapezoidal with the longest side posterior and open, the angles or points of
the ‘W’ being the apodemes. Posterior to this frame is a band of membrane
which is invested narrowly over its width by deciduous hairs or scales, the
bases remaining. The sternite is probably a modification of the framed,
corematous type, where the coremata have disappeared with shortening and
broadening of the whole sclerite, bringing distal hair pencils (e.g. as seen in
some members of the Saroba group such as Tamba
Walker;
p. 357) adjacent to the remnants of the frame along the anterior margin. The
eighth tergite is of a form seen in other groups of genera, where the splayed
anterior apodemes converge into a narrow central strip that broadens distally
into a slight pocket that opens anteriorly.
In some
species there is a juxta in the male genitalia that appears to be formed in the
typical catocaline manner (p. 18) with an inverted ‘V’ structure arising
from the sacculi of the valves (e.g. Fig 789). The female genitalia have the
ductus bursae arising from the base of the corpus bursae in a slight,
posteriorly directed, tapering appendix bursae, similar to that seen in Oglasa
Walker
and Chorsia
Walker
(p. 406), which are in the group of genera with the type of male eighth tergite
described above, but with the sternite more completely ‘framed’ and
containing coremata. The corpus bursae may contain spines, e.g. a prominent
group in Metalectra
praecisalis Hübner, the type species, but no definite signum has been noted.
The ostium bursae is situated at the junction of segments 7 and 8.
The
clypeofrons is unscaled as is typical for quadrifine groups, but the placement
is not clear. There are two further instances of fungus-feeding in the
quadrifines (Rawlins, 1984), both attached to family-group names, but the
relationship to this Metalectra group needs further investigation.
The
tribe Scolecocampini of Grote (1883) is based on the New World Scolecocampa ligni Guenée (= liburna
Geyer).
The larva bores in decaying wood of deciduous trees and may in fact be feeding
on the fungus within them (Covell, 1984). The facies is not close to that of the
Metalectra
group,
with highly dissimilar fore- and hindwings, the forewings much paler and narrow,
the hindwings uniform. The male abdomen has the eighth tergite as in the Metalectra
group,
but the sternite is of the completely framed type, the diaphragm within the
frame being very slightly corematous. The male genitalia show no obvious
similarities, but the female has a slight appendix bursae of the type described
above, and the corpus bursae is ringed centrally with a band of numerous slender
spines directed distad that might be homologous with the smaller group of much
larger ones, similarly oriented, seen in Metalectra praecisalis.
The ostium is set at the anterior margin of the eighth segment, covered by the
curved posterior margin of the seventh sternite. The larva has significant
reduction of the prolegs on A3 only (Godfrey, 1987), whereas those of A4 are
absent in larvae of Bornean genera where known.
The
Boletobiini of Grote (1895) are based on Boletobia Boisduval,
a junior synonym of Parascotia Hübner. The type species, fuliginaria
Linnaeus,
feeds on bracket fungi (Polyporaceae) and has facies more similar to that of the
Metalectra
group
with fore- and hindwings similar in pattern, but this is more regular, boarmiine-like,
with pale wavy fasciae on black. The male antennae are bipectinate, a feature
seen in Veia Walker of the Metalectra group,
but not generally. In the male abdomen the tergite is much broader than in the Metalectra
group
or Scolecocampa,
but the sternite, though more flimsy, appears similar. The male genitalia
structure is also compatible. However, in the female, the ostium is set well
within the seventh segment, where the sternite has become much reduced, and the
lateral margin of the tergite appears close, separated only by the ostium (see
also the account of Maguda Walker on p. 388). The ductus and bursa are short,
small, the latter without ornament. Therefore the Metalectra
group
is assigned to the Boletobiini tentatively.
The
early stages of Parascotia appear to be similar to those described for Diomea
Walker
below, and have been described by Swain (1950); see also South (1961) and
Bretherton et
al. (1983).
The prolegs of A3 and A4 are completely absent, and the primary setae are borne
on tubercles or chalazae. The mode of pupation also appears to be similar,
except the cocoon is suspended at each end by a thread like a hammock. The
prolegs of A3 and A4 are also absent in Metalectra (Crumb,
1956). Fungus-feeding larvae have also been noted in Japan for the genera Hypostrotia
Hampson
(Mutuura et
al.,
1965) and Anatatha Hampson (S. Yoshimatsu, pers.
comm.);
in the latter the prolegs of A3 and A4 are absent as is typical for the
Boletobiini (Yoshimatsu, in prep.).
If these
genera should all prove to form a natural group, there remains the question of
their wider relationship. Forbes (1954) placed Metalectra
in
his second miscellaneous series of genera after Pangrapta Hübner,
citing Richards (1933) as considering them “the most primitive of proper
Erebinae”, and before Scolecocampa. Scolecocampa and
Metalectra
are
included in the Catocalinae by Hodges et al. (1983), though Parascotia
is
placed in the Rivulinae. Rawlins (1984) referred Parascotia to
the Herminiinae. Bretherton et al. (1983) treated Parascotia
under
the Ophiderinae but noted it had previously been placed in the Hypeninae.
Nielsen et
al. (1996)
placed component genera such as Artigisa Walker and Panilla
Moore
in their concept of the Hypeninae. Fibiger (2003) placed Scolecocampa
in
the Catocalinae and Parascotia in the Calpinae, though does not include the latter
as a third European representative of the calpines. A further distinction of Scolecocampa
from
the Boletobiini is its lack of phragma lobes at the anterior of the second
abdominal tergite.
The most
conservative solution is probably to retain this fungus-feeding group for the
time being within a broad concept of the Catocalinae, associated with other
genera or generic groups with a similar structure of the male eighth tergite
such as, possibly, the Saroba group.
Several
species of Diomea and one of Maguda Walker
were attracted to fruit traps in Sulawesi during Project Wallace in 1985. This
may prove to be an effective means of surveying this group in conjunction with
light-trapping.
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