20
but others could almost certainly be found in
suitable sandy habitats.
Bombylius major is generally distributed
throughout Essex. It is variable in size averaging
about 11 mm, its legs are long and thin, its
body squat and covered in dense, fine hair. The
single pair of wings (all true flies have just
one pair of wings) are clear with the fore-
margin darkened almost to the wing tip. The
eyes are large and the proboscis is long and
thin.
Bombylius is beautifully adapted in all its
stages for its special way of life. The adult
is essentially an aerial feeder and in early
spring can be seen hovering in front of flowers,
sometimes steadying itself with its fore
legs and probing flowers with its long proboscis
for nectar, very much like a humming bird. Its
flight is silent and fast with frequent,
apparently motionless periods of hovering.
The adaptations of the adult however exquisite
are no match for the larval stages. The female
generally broadcasts the eggs close to the
ground in the vicinity of the nest holes of
solitary bees.
The first stage larva is a thin worm-like form
which actively searches out a solitary bee nest
where it will enter and for a while live on the
honey and pollen store.
When the bee larva is grown the fly parasite
undergoes a change and becomes a sedentary more
typical maggot type larva, which sucks the
juices from the bee in a manner which ensures
that the bee pupae stays alive as long as
possible. As the bee is finally consumed the
fly larva reaches maturity and then pupates