Laboulbeniales

Laboulbeniales is an order of fungi within the class Lecanoromycetes.

These include the obligate insect parasites, with cellular thalli, predisposing this fungi to certain death without an insect host.

Laboulbeniales does not have any hyphae, instead parasitising its host through a black foot cell, which penetrates the insect tissue, allowing the fungus to access nutrients within its body.

Trivia

 * Entomologists once thought that these fungi were actually morphological characteristics of the insect hosts they parasitized, until a mycologist by the name of Mayr, looked under the microscope and declared it an fungus.
 * These fungi can be some of the most host-specific parasites, even going so far as to have a preference for sides on a fly (left side, due to mating behavior)!