Mycangia of ambrosia beetles
Ambrosia beetles evolved a variety of morphological structures to carry their fungal symbionts from tree to tree. These structures are generally called mycangia. A nice classification of mycangia was published by Diana Six (Six, 2003). The main difference between different kinds of mycangia is whether or not they are external or internal, and whether they secrete substances relevant to the fungus containment or not.
In case of nonglandular mycangia on the surface, it is not clear that they actually really serve that purpose. In cases where no mycangium has been found, spores or conidia of ambrosia fungi may be carried in the beetle’s digestive system (Biedermann, unpubl.)
Some people use the term “mycetangia”, but this often refers to a cluster of cells within an organ that house mutualistic endocytobionts inside the body cavity (Ganter, 2006). This is mostly called mycetocyte. More commonly it houses symbiotic bacteria, and then it is more properly called “bacteriocyte”.
Ganter, P.F. (2006). Biodiversity and Ecophysiology of Yeasts. In The Yeast Handbook, pp. 303-370. Springer, Berlin Heidelberg.
Six, D.L. (2003). Bark beetle-fungus symbioses. In: Insect Symbiosis. Bourtzis, K. and Miller, T. A., eds. CRC Press, New York, pp. 97-114.