Laboulbeniales, an order of fungi in the class Laboulbeniomycetes (phylum Ascomycota, kingdom Fungi) that includes more than 1,800 species, which live off the chitin (exoskeleton) of arachnids (e.g., spiders) and insects. The minute species are highly specialized, some attacking only specific areas on one sex of the host species. Asexual reproduction does not occur.