Tholymis tillarga (Fabricius, 1798), the Coral-tailed Cloudwing, is a species of dragonfly found from tropical West Africa to the Pacific Islands. It is a medium sized red dragonfly with brown and white hindwing patch. Tholymis tillarga female and immatured male have similar wing pattern: both wings are transparent with the hind wing translucent brown near the base. Matured Male has additional opaque white patches beside the brown patches that look like cloud hence the common name Coral-tailed Cloudwing.

In males, the abdomen is 28 to 33 mm, hindwing is 33 to 37 mm and the total body length ranges from 44 to 47 mm. The face is rusty brown with a crimson flush. Eyes brown capped with reddish olivaceous below. Thorax reddish above golden yellow or olivaceous on sides. Legs rustybrown. Wings transparent with a broad fan shaped golden brown patch on the hindwing. This is bordered by a milky white patch. Wing spot reddish brown. Abdomen bright rusty-red. 

The female is pale brown in colour, without the white patch on the hindwing. The abdomen is 27 - 31 mm, hind wing 31 - 37 mm. Head and thorax olivaceous without any red tinge. Hindwing brown without the milky white border and the brown patch is very pale and obscure. Abdomen olivaceous brown. The immature male looks like a female.

It is a crepuscular dragonfly, active at the time of sunset and flies at night. Frequently comes to light at night. This fast flying dragonfly is very difficult to follow. Commonly found in ponds, marshes and tanks. 

The species has a wide distribution in all parts of the world except Europe and the Americas. It is widespread in Africa, Asia, Australia, and Indian Ocean Islands. In Africa, it occurs in every country south of the Sahara. In Asia the species extends throughout India, eastwards to southern China and Japan and southwards throughout southeast Asia to Australia, New Guinea, Micronesia and Samoa. This is a widespread and disturbance tolerant species with no known major widespread threats. It is therefore assessed by IUCN Red List as Least Concern.