Base of leg gland -

…The antennal gland consists of a coelomic pouch, labyrinth, renal duct, and bladder. In freshwater species, the renal duct is long and is involved in osmotic regulation of body fluids, allowing the excretion of urine that is thinner than body fluids. In spiders, the base gland is an excretory organ derived from the nephric duct, but they also have Malpighian tubules. In insects, there is no excretory organ derived from the nephric duct, and the Malpighian tubules perform the excretory function. …

*Some of the terminology that mentions the "peduncular gland" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…触角腺は体腔囊･迷路･腎導管･膀胱からなり，淡水産の種では腎導管が長く，体液の浸透圧調節に関与して，体液より薄い尿を排出できる。クモ類は脚基腺が腎管由来の排出器官であるが，マルピーギ管をももつ。昆虫類には腎管由来の排出器官はなく，マルピーギ管が排出機能を営む。…

※「脚基腺」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報