Bijoaraneus mitificus is a species of orb-weaving spider found primarily in South America. Belonging to the Araneidae family, this spider is noted for its intricate web-spinning behavior, which is characteristic of orb-weavers. The adult spiders have a distinct appearance with a body length of about 10-15 mm. Females are larger than males, which is typical of the species. Their coloration can vary, but they often exhibit a reddish-brown to dark brown body with a pattern of lighter markings on the abdomen, which helps with camouflage in their natural environment.

The abdomen is usually rounded and bulbous, with long, slender legs that are covered in fine hairs. These legs enable the spider to move quickly through its web to capture prey, such as small insects. B. mitificus is a nocturnal hunter, primarily active during the night when it repairs its web and waits for prey. Their webs are built in low vegetation or near human dwellings, particularly in tropical and subtropical forests. This spider is non-aggressive towards humans and uses venom to immobilize its prey, though its bite is harmless to humans.

Its ecological role includes controlling insect populations, making it beneficial in both wild and cultivated areas.