This family was originally an order thought to be included with the aquatic Phycomycetes and included members of Oomycota. It was Berdan (1938)  who determined that Ancylistes belongs to order Entomophthorales. Later, the oomycetes were removed as were several zygomycete genera.
The mycelium is coenocytic or irregularly septate. The nuclei are small. During interphase, condense chromatin is absent, but a central nucleolus can be observed. The mycelium can become disjointed. In Ancylistes, parasites of desmids, the hyphae grow toward the ends of the host. As the hyphae grow, branches that follow the groves between plates in the chloroplast are produced. Upon reaching the end, the hyphae grow toward the other end to completely encircle the chloroplast. Sepata are produced progressively with segments containing many nuclei. Conidia are produced singly on unbranched sporophores. Like other members of Entomophthorales, conidia are forcibly discharged, which occurs through papillar eversion. Zygospores are formed along the axis of conjugation  and can be angular in shape.
Sexual reproduction results in the formation of a zygospore that functions as a resting spore. The zygospore is formed by the fusion of gametangial cells or the scalariform fusion of hyphae. Little is known about the zygospores.
The genus Ancylistes are parasites of desmids, a group of green algae. Macrobiotophthora are parasites of tardigrades and nematodes. The genus Conidiobolus are common saprobes and occasional parasites of vertebrates. The most well known member is Conidiobolus coronatus, which is typically found in soils and parasitizing termites and aphids but has been known to infect mammals.