Lots of flowers were still in bloom, most obviously Rosebay Willowherb, Chamerion* angustifolium. It was once known as Epilobium angustifolium (and still is, in some books) but whereas Epilobium species have actinomorphic (radially symmetrical) flowers, those of Chamerion species are zygomorphic (bilaterally symmetrical) flowers.
Rosebay Willowherb is often abundant on waste ground. Byfield
Pocket Park, 4 September, 2019
The picture shows that whereas four of the petals are broad, the fifth (lowest) one is narrow, giving the zygomorphic form. This is one of the food plants for the caterpillar of the Elephant Hawkmoth, but I searched for them in vain today.
Perhaps more important for insects are the broad, saucer-sized umbels of Hogweed, Heracleum sphondylium. With nectar accessible to even short-tongued insects the flowers attract a wide range of species, and that was the case today.
Tachina ferox on hogweed. Byfield Pocket Park.
The yellow and black tachinid fly, Tachina ferox, is a common and distinctive insect. So many were about today that in some cases an umbel was hosting two or more specimens. The caterpillars of larger moths need to beware as these flies will leave their larvae in a suitable spot; they will then parasitise a passing victim.
Two, and sometimes more, specimens of Tachina fera were present on
hogweed umbels. 4 September, 2019
The best I could manage: Xylota sylvarum on ivy blossom.
4 September, 2019