As for many entomologists, Philip P. Calvert's interest in insects began with butterflies. The following gallery of watercolor drawings of butterflies were done by Calvert in 1885 at the age of 14. The originals are in the Ewell Sale Stewart Library, Academy of Natural Sciences of Philadelphia. The examples below are scanned from slides and do not capture the full vibrancy of the originals. All are reproduced with permission of the Ewell Sale Stewart Library.
 

Last instar larvae, crysalis, and adult of the Eastern Black Swallowtail, Papilio polyxenes.

Tiger Swallotail, Pterourus glaucus.

Zebra Swallowtail, Eurytides marcellus.

Buckeye, Junonia coenia.

Common Sulphur, Colias philodice.