瑜伽師地論略纂 2.54

2.54

五觸中，蚊虻為二故。六中，俱生為第四，內身之中與身俱故。所治即垢等，能治即水等。

Among the five contacts, mosquitoes and gadflies are counted as two. Among the six, co-arising is the fourth, because it is together with the body within the internal body. That which is treated refers to dirt and the like; that which treats refers to water and the like.