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Members of the genus Platycoelia Dejean
are usually 1-3 cm in length with lime green
to olive green coloration. A total of 62 species
are known, and the larvae of two species have
been described. Species of Platycoelia are
most diverse through the Colombian to Bolivian
Andes. They are common in mid-elevation
to high elevation habitats in the Andes Mountains
and other montane areas of the Neotropics.
Unusually small, dark, and setose
species are found at high elevation (3,000-
4,000 m) in the Puna and Altiplano regions of
Perú and Bolivia.
Very little is known of the biology of Platycoelia
species. The larvae have been found
feeding on organic material in the soil (Ohaus
1908, 1909a). Adults feed on the foliage of
various types of plants and are sometimes attracted
to lights at night. The adults of some
species have a short life span and emerge in
great numbers to rapidly breed and lay eggs.
This is the reason why many abundant species
are known from only a handful of museum
specimens. Collectors usually have only
a narrow window of opportunity in remote locations
of poorly known regions. Whymper
(1891) discussed an example of this when he
observed “many hundreds” of P. lutescens
Blanchard individuals spread over a large
area on the plains near Volcán Cotopaxi in
Ecuador. He remarked that the “region has
been traversed by several, at least, of my predecessors”
(who would have collected specimens
if they saw them). Whymper noted that
the beetles were large and very obvious because
of their abundance and the scarcity of
vegetation in the area. There are also examples
of Platycoelia known from only a very
large type series originating from a single collecting
event (P. inca n. sp. and P. haenkei
[Gutiérrez] are examples). There are undoubtedly
more species of Platycoelia with shortlived
adults that have not yet been discovered.
Indiscriminant collecting probably accounts
MONOGRAPHIC REVISION OF PLATYCOELIA 3
INTRODUCTION
The genera of the cockchafers offer few species as remarkable as this one.
—Pierre André Latreille 1813
(when describing the first species of Platycoelia)
for the skewed sex ratios seen in collections
for several species of Platycoelia. As with
many other insects, the adult males tend to
emerge first, followed several days later by
the females (which probably live longer). The
sex ratio of specimens captured can vary
widely from day to day, especially for the species
with short adult life spans. Males and females
may have different propensities to
disperse and that probably also has an effect
on the sex ratio of collected specimens.
At certain times of the year, Platycoelia
adults are used as food by the indigenous
people of the Ecuadorian highlands (and undoubtedly
other places). Onore (1997) reported
that five species of Platycoelia were
regularly consumed in Ecuador, while Smith
and Paucar-Cabrera (2000) detailed the use of
P. lutescens as food. Ecuadorians call greencolored
Platycoelia “catso verde” and whitecolored
Platycoelia (mainly P. lutescens) “catso
blanco.” David Hawks (UCRC) and Ron Cave
(EAPZ) informed me that they call Platycoelia
“watermelons” or “poor man’s Chrysina”
when collecting in the mountains of Central
America for jewel scarabs. I, of course, take
exception with the latter name!
The large size and appealing coloration of
the genus Platycoelia made it a popular group
with 19th century collectors and explorers. As
a result, many species were described over a
century ago. Friedrich Ohaus (1904b) published
the most important Platycoelia paper
to date when he revised the group in 1904. His
work, however, did contain several mistakes
and has proven to be an ineffective identification
guide (based on the high percentage of
unidentified and misidentified specimens in
collections around the world). It did not even
contain a key to the species level. Ohaus’ taxonomic
work on Platycoelia is now badly outdated.
Over the past 98 years, South America
has become tremendously more accessible,
and people have collected insects in many new