One last department of the great undertaking to which Ray had dedicated himself on leaving Cambridge and to which his friend Dr Tancred Robinson was constantly exhorting him still remained unfulfilled. He had published the Synopsis of British Plants in 1690 and the supplementary Sylloge of European Plants in 1694. The Synopsis of Animals and Reptiles had appeared in 1693 and that of Birds and Fishes had been sent to Dr Robinson on 29 February 1694. There remained the Insects—a tribe including, in those days, everything from an amoeba to an earthworm; and to these he turned with an energy amazing but characteristic.

It is indeed an almost heroic achievement. He was living in considerable poverty at Black Notley, remote from any libraries or collections and from contact with friends and fellow-workers. He was maintaining his other interests—in theology, in botany, and the general field of natural studies. He was constantly pressed to fresh labours by the importunity of his friends, and in 1693 edited his Collection of Curious Travels and Voyages at the request of Charles Hatton and Hans Sloane.