Primarily a parasitic Hymenopterist but also collected other insects including beetles. He was closely associated with the young J.H.Keys and his father, and like JHK was a keen microscopist/micro-photographer. His obituary by J.H. Keys in Ent.mon.Mag, 46, 1910, 94-95, mentions that on a trip to Corsica, with his friend T.A. Marshall, his wife found ‘the unique Anthribid which is now the type of a new genus and species Spathorrhamphus corsicus.’
Most of his collection is in Plymouth Museum (includes Hemiptera, Lepidoptera and Coleoptera) see www.plymouth.gov.uk/museumbignellcollection (Information from Helen Fothergill), and Tony Irwin informs me that there are a number of insects bearing the initials GCB in E.A. Butler's foreign collection of Coleoptera and Hemiptera at Norwich Museum.
Gilbert (1977) lists two further obituaries (MD 10/03, 11/09)