''Illyria viridis'', the yidiyidi, is a species of singing cicada found in Western Australia. The genus ''Illyria'' was created in 1985 by Australian

entomologist Entomology () is the scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arach ...

Maxwell Sydney Moulds Maxwell Sydney Moulds is an Australian entomologist. The majority of his books are written about Cicadas.specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''viridis'' is the Latin adjective meaning green, and pertains to the insect's green colour. The local Wuggubun community call this cicada "yidiyidi".

Distribution and habitat

Only a region within 150 kilometres of Kununurra, in the far northeastern region of Western Australia, is home to the yidiyidi. Adults inhabit tall grass, which grows near little water channels, typically in a mixture of both live and dead leaves. Adults start to appear after the first rains of December, and become locally widespread until at least mid-February.

Description

The yidiyidi has a brown head, that becomes pale toward the eyes and is deepest around the ocelli, and it frequently has a pale green tint. The eyes themselves are pale tan. The postclypeus is brown and resembles the color of the ocelli, it darkens at the apex. The insect has a brown rostrum that becomes black at the tip as it reaches the bases of the hind coxae. The thorax is pale brown on the ventral side, and green dorsally. The pronotum frequently has a narrow black or dark brown fascia on either side of the midline, which together with the anterior pronotal margin and pronotal collar form an inverted keyhole shape. There are also frequently irregular black or brown markings along sutures that extend laterally next to the paranota and onto the pronotal collar lateral angles. Scutal depressions; black submedian and lateral sigilla on the mesonotum, with the latter occasionally reticulate. The forewing is

hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

; costa is light yellowish to brown, frequently with hints of green; most other venation on the basal half also light yellowish brown, and black next to the basal membrane. The venation on the distal half of the wing is dark brown or black. The legs are yellowish brown to dark brown. The fore femora have small spines. The meracantha is dark brown basally and pale yellow distally. A large black suffusion covers the anterior distal half of the opercula, which are wide and rounded. The opercula are pale yellow. Sternum is golden brown to midbrown, but always lighter than tergites; abdomen with brown tergites, sometimes deeper or leaning toward black. Both male and female yidiyidi measure around 16 mm in length (including the

ovipositor The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...

for females). The length of the forewing averages 20.6 mm for the male, and 19.2 for the female. The head is around 5 mm wide and the pronotum is about 6 mm across.

References

{{Taxonbar, from=Q114129554 Hemiptera of Australia Macrotristriini Insects described in 2022