17.
their habit of flitting so quickly from tree to
tree and then remaining motionless on a leaf for
several minutes before flying again. I also
watched an Emperor Dragonfly chase a Purple
Hairstreak but it may have been just an investi-
gation as it soon left it alone. The Purple
Hairstreak is quite definitely in one of its
periodic abundant years, and I have even seen
them in my garden in suburban Buckhurst Hill.
Several large patches of creeping thistle
were noticeable a short distance away because
of the constant flow of insect activity about
the flower heads. I stopped to watch and
identify many of the species, disturbing a
common lizard in the process, which quickly
disappeared into the grass. Among the bees
gathering nectar at the flowers were Bombus
lucorum, Bombus lapidarius, easily recognised
by the orange-tipped abdomen, the rest of the
insect being black, Bombus pratorum and Apis
mellifera, the honey bee. There were many
butterflies feeding as well, Small Skipper,
Common Blue, Holly Blue, Small Copper, Hedge
Brown, Meadow Brown and perhaps rather sur-
prisingly a White-Letter Hairstreak. There
sure enough was the brown underside with the
white dotted "W" and the very noticeable "tails".
This was a surprising sight as I have never
observed it in the wild before and in the Essex
Naturalist's Trust Guide to the Larger
Lepidoptera of Essex it gives the distribution
as rather easterly and southerly in Essex,
though this area would seem to be well quali-
fied for maintaining this butterfly as I have
seen both Common Elm and Wych Elm which is the
larval food plant growing in the vicinity.
Also noted were many Syrphidae feeding on the
flower heads of the thistle. Eristalis tenax
(the adult of the rat-tailed maggot)wasquite
common and one Volucella pellucens was noted
(the species with the opaque white and black
abdomen) and I also saw three specimens of the