Wildlife officials caught the two in possession of about 500 rare insects in Srikhala, a town near Darjeeling in West Bengal state, in June, according to the Wildlife Trust of India, a group that worked with government investigators.
The court in Darjeeling fined Petr Svacha, an entomologist, $500 and sentenced his associate Emil Kucera to three years in prison. Kucera also was fined $1,500.
The court released Kucera on bail of $150 pending an appeal.
The Czech citizens said they collected the specimens for research purposes. However, they were traveling in India on tourist visas that did not allow them to work, said Govind Chhetri, a lawyer for the wildlife department.
Chhetri also said Kucera had a Web site to sell insects. He gave no other details.
Svacha and Kucera's lawyer, Taranga Pandit, said Kucera did not sell prohibited insects and had been collecting specimens for research work.
"Most of them were not endangered. They may have collected one or two unknowingly," Pandit said.
The Czech ambassador to India, Hynek Kmonicek, who was at the hearing, told The Indian Express newspaper he was surprised the court handed down two different sentences for the same offense.
The judge, U.K. Nandi, said the court had taken into account the fact that Svacha was a well-known entomologist.
The two men plan to appeal their sentences in a higher court, Pandit said.