Johnston's organ

Japanese: Johnston's organ（英語表記）Johnstonsorgan

…In addition to the tympanic organ, chordotonal organs, which consist of a relatively small number of sensilla, are located near the joints of the body, such as the antennae and the legs, and act as proprioceptors, although some also detect wing movement. In addition to the tympanic organ, other chordotonal organs, which are made up of a large number of sensilla, include the subgenual organ and Johnston's organ. The subgenual organ is located in the legs and is a sensitive receptor for floor vibrations, while the Johnston's organ is located in the antennae and is generally said to be related to the perception of gravity and other accelerations, but in dipterans such as mosquitoes and flies it functions as an auditory organ. …

From [Hearing]

…Flies and mosquitoes are also known to hear and respond to wingbeats. Their hearing organ is the Johnston's organ in the antennae. The feathery antennae resonate with low-frequency sounds such as wingbeats, which stimulate the Johnston's organ at the base of the antennae. …

*Some of the terminology that mentions "Johnston's organ" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…鼓膜器官以外には，比較的少数の感覚子からなる弦音器官が触角や足などの体の関節近くにあり自己受容器として働くが，羽の動きを受容するものもある。多数の感覚子が集まってできた弦音器官としては，鼓膜器官のほかに膝下（しつか）器官subgenual organ，ジョンストン器官Johnston’s organがある。膝下器官は足にあり，床の振動の敏感な受容器であり，ジョンストン器官は触角にあり，一般には重力その他の加速度受容に関係するといわれているが，カやハエなど双翅（そうし）類では聴覚器として働く。…