Complex sentence: The adult flies will typically will feed on pollen and nectar of flowers, while the larvae are endoparasites that feed mainly on the nostrils of the Common Toad ("Bufo bufo"), though they have been found as parasitises on other frog and taod species.
Split into simpler sentences: The adult flies will typically will feed on pollen and nectar of flowers. The Larvae are endoparasitises and feed mailly on the nostrils of the Common Toad "Bufo bufo", though they have been found as parasitises on other frog and taod species.