The evolution of certain orchids in
tropical America is related to the presence
of euglossine bees (tribe Euglossini,
subfamily Bombinae-closely allied
to the honey bees and especially the
buLmblebees). Male bees are specifically
attracted to certain fragrances. This
phenomenon has been partially eluLcidated
during the past 10 years. The
visits of euglossine bees to orchids were
first reported by Cruger (2) and discuLssed
by Darwin (3) in his classic
treatise on the modifications of the
orchid flower. In suLcceeding years there
were additional reports of euLilossine
bees visiting orchids, but in all cases
the observers assumled that the bees
were visiting the flowers to obtain some
kind of food. The flowers involved do
not contain nectaries, and it was thtts
assumed that the bees gnaw on the
flowers. Observers may have been Imiisled
by flowers that had been partly
eaten by crickets, cockroaches, or other
chewing insects. Ducke (4) made many
observations of euglossine bees and
noted that only male bees were visiting
most orchid flowers, but he also believed,
as did Porsch (5) and Allen (6),
that the bees were eatina the flower
tissues. Dodson and Fry mire (7) were
the first to note that the bees do not
chew on the flossers, but scratch or
brLish on the surface, frequently