Theodore Pergande (28 December 1840 – 23 March 1916) was a German-born American entomological pioneer known for his skills in rearing insects.

He made careful observations on aphids and thrips and made collections and studies on North American ants, several of which, including the harvester ant Messor pergandei and the scale insect Parlatoria pergandii, have been named after him.

Pergande was born in Germany and moved to the United States at the beginning of the American Civil War and served in the northern army.

[1] After the war, he lived in St. Louis where he married a German, worked in a gun-making company, and collected insects on weekends.

[2][3][4] Pergande was among the oldest members of the Entomological Society of Washington and was among the several other influential entomologists of German origin along with Hermann August Hagen, Eugene Amandus Schwarz, George Marx, A.J.