Wiktionary
prothoracic gland
n. (context biology English) Either of a pair of glands, in the prothorax of insects, which produce ecdysone
Wikipedia
Prothoracic gland
The prothoracic glands are either of a pair of endocrine glands located in the prothorax of certain insects that regulate molting. They have an ectodermal origin and secrete ecdysteroids, such as ecdysone and 20-hydroxyecdysone.