He contributed much to the geology, palaeontology and zoology of the West Indian region, in particular Trinidad.

He was one of four children of Robert Guppy (1808–1894), a lawyer who went to Trinidad and became Mayor of San Fernando, and Amelia Elizabeth Guppy, a painter and one of the pioneers of photography, who navigated the Orinoco River accompanied by only a few native Indians.

Lechmere wrote and published numerous articles on the malacology and palaeontology of the region.

He served as President of the Scientific Association of Trinidad, as well as of the Royal Victoria Institute Board.

Although Girardinus guppii is now considered a junior synonym of Poecilia reticulata, the common name "guppy" still remains.