[3] It develops in a chemically induced gall; a sub-spherical distortion rising up from the upper surface of the leaves of alder trees Alnus glutinosa along the midrib.

[3] The gall's appearance on the upper surface is sub-spherical, smooth and may vary in colour from pale yellow-green to deep red.

The adult mite lives on alder tree sap, sucked from the cell tissues.

[4][5] The wide opening and interior on the lower epidermis and is lined with large numbers of small hairs.

[3][4] The galls induced appear not to affect the health of trees infected with these mite species and no practical way of controlling or preventing them exists.