Thopha saccata, the double drummer, is the largest Australian species of cicada and reputedly the loudest insect in the world.

Documented by the Danish zoologist Johan Christian Fabricius in 1803, it was the first described and named cicada native to Australia.

Its common name comes from the large dark red-brown sac-like pockets that the adult male has on each side of its abdomen—the "double drums"—that are used to amplify the sound it produces.

Found in sclerophyll forest in Queensland and New South Wales, adult double drummers generally perch high in the branches of large eucalypts.

Danish naturalist Johan Christian Fabricius described the double drummer as Tettigonia saccata in 1803,[1] the first description of an Australian cicada.

[10] The adult double drummer is the largest Australian species of cicada, the male and female averaging 4.75 and 5.12 cm (1.87 and 2.02 in) long respectively.

The head, antennae and postclypeus are black,[14] with a narrow broken pale brown transverse band across the vertex just behind the ocelli.

[14] The pronotum is rusty brown with black anterior borders, while the mesonotum is a little paler with prominent black markings,[11] with paired cone-shaped spots with bases towards the front on either side of a median stripe;[10] lateral to these spots are a pair of markings resembling a "7" on the right hand side of the mesonotum and its reverse on the left.

[12][23] The narrow spindle-shaped eggs are laid in a series of slits cut by the mother's ovipositor in branches or twigs, usually of eucalypts.

[25] Though the timing of the double drummer's life cycle is unknown,[26] nymphs of cicadas in general then spend from four to six years underground.

They are found in dry sclerophyll forest, preferring to alight and feed on large eucalypts[13][14] with diameters over 20 cm (7.9 in) and sparse foliage concentrated at a height between 10 and 25 m (33 and 82 ft),[13] particularly rough-barked species,[10] apples (Angophora) and Tristania.

[11] Associated trees include the grey box (Eucalyptus moluccana), snappy gum (E. racemosa) and narrow-leaved apple (Angophora bakeri) in a study at three sites in western Sydney.

[34] At Hawks Nest in coastal swampy sclerophyll woodland, adults were observed mainly on swamp mahogany (Eucalyptus robusta) and sometimes blackbutt (E. pilularis), as well as Allocasuarina littoralis and introduced pine (Pinus radiata).

[2] In hotter weather, double drummers perch on the upper branches of trees, while on overcast or rainy days, they may be found lower down on trunks near the ground.

[13] The double drummer has been known to fly out to sea, effectively on a one-way trip as their bodies have later been found washed up on beaches.

A swarm of double drummers were reported 8 km (5.0 mi) off the coast of Sussex Inlet in January 1979, in and around the boat of a local fisherman.

They are then shoved into the hunter's burrow, where the helpless cicada is placed on a shelf in an often extensive "catacomb", to form food-stock for the wasp grub growing from the eggs deposited within.

[39] Poems dedicated to the double drummer appeared in the Catholic Press in 1933 and 1936, describing bird predation and its life cycle to children.