Fungal Gall Caused by a New Species of Ledomyia (Diptera: Cecidomyiidae) on Xylaria enterogena (Ascomycetes: Xylariaceae)

Galls on the stromal surface of Xylaria enterogena (Mont.) Fr., collected in Venezuela, are caused by a new species of cecidomyiid, Ledomyia collarata Gagné, which is described here. The gall extends the record of fungus/insect interactions; it is the first fungus-composed gall known to enclose and house an insect completely on an ascomycete. The last instar bears a noteworthy prothoracic collar that, with the sternal spatula, forms an almost continuous ring around the head capsule. The gall is constructed entirely of fungal tissue, with an exposed wall composed of three layers; a thick carbonaceous layer is the most distinctive.