after Jürgenstein et al., 2015
Male terminalia. Posterior margin of gonocoxite ventromedially with shallow convexity, and with abrupt and blunt projections laterally. Posterior impression with narrow base and well widened posterior part. Anterior impression with anteriorly evenly divergent narrow arms. Ventral branch of gonostylus with symmetrical semi-oval posterior process, which bears minute warts and few setae on ventral surface; spine 1 wide, sharply pointed; spine 2 similar or somewhat longer but more slender; spines 3 and 4 about twice as small, evenly tapering and with about equal distance between each other and spine 2. Ventral branch of gonostylus with 4–5 strong bristles deviating from other setosity laterally on ventral surface. Dorsal branch of gonostylus steeply tapering; lateral margin with deep concavity; proximal posterior process about twice as high as distal posterior process, both separated by deep concavity. Distal posterior process with apical small setula and with a basal strong seta deviating from other setosity; proximal posterior process apically rounded with 1–2 strong basal setae deviating from other setosity. Posterior margin proximally from medial bristle with 4–5 gradually diminishing bristles followed by 3–4 smaller setae; internal surface with a stronger seta next to the medial bristle. Basal angle clearly outlined, angular or somewhat rounded; basal margin with few setae. Ejaculatory apodeme with campanulate base and without rim. Aedeagus oval or cross shaped. Aedeagal guides extending over apical part of aedeagus; apically rounded and divided into two lamellae; with lateral impressions very small. Aedeagal apodemes laterally slightly angular or arched and pointed apically.
Intraspecific variation. In some cases the lateral margin of the dorsal branch of the gonostylus is shallower, and the distal posterior process and the posterior margin of the dorsal branch of the gonostylus resemble those of M. uninotata. The spine 2 on the ventral branch of the gonostylus compared to the spine 1 can be more prominent than described by Laštovka (1972).
Hosts. Known from many species of Agaricales and Russulales (Kurina 1991, Yakovlev 1994, Chandler 2010, Ševčík 2010). Material from pine dominated boreal forests in Estonia indicates specialisation to Lactarius (Russulales) and Cortinarius (Agaricales).