So far as I am aware no attempt has ever been made to work up the Hymenoptera of Cambridgeshire since the Rev. Leonard Jenyns collected here during 1824–1849; his collection, named by Fred. Smith, is in the University Museum at Cambridge, and it is from it that we must gather a general idea of the bees, saw-flies and ichneumons of the county. As long ago as 1797, the Rev. William Kirby traversed the fens, and has left some account of the species he observed in his Journal; and both Stephens and Curtis mention isolated captures at Cambridge and Whittlesea Mere. To this ancient and more or less unreliable material, I have only been able to add a few records of the Parasitica by Bridgman in the Trans, of the Entomological Society, 1882–89, and an occasional mention by Saunders in his Aculeata of the British Islands, 1896. Several species have been sent to me thence by Cross, Thornhill, Tuck, and Donisthorpe; and in 1902 I spent a week at Wicken, but the weather was so inclement that but few captures of even the commonest insects were effected.

Altogether only 173 species appear to have been noted in Cambridgeshire, and of these 35 appertain to the Saw-flies, 68 to the Aculeates, and 70 to the Parasites; but many of the older records must be received with due caution, especially among the Tenthredinidae and Ichneumonidae.