Dilacreon Fennah, 1980

Löcker, Birgit, Fletcher, Murray J. & Gurr, Geoff M., 2010, Taxonomic revision of the Australian Eucarpiini (Hemiptera: Fulgoromorpha: Cixiidae) with the description of nine new species, Zootaxa 2425, pp. 1-31 : 7-8

Genus Dilacreon Fennah, 1980

Dilacreon Fennah, 1980: 242 .

Type species: Dystheatias orpheus Fennah, 1956: 78 , by original designation.

Morphology. Body length: 3 3.9–4.9 mm; Ƥ 4.0– 5.2 mm.

Head: Head including eyes about as wide as or wider than pronotum. Vertex with distinct or indistinct median carina covering entire length of vertex; lateral carinae slightly elevated; anterior margin of vertex straight or convex; subapical carina absent. Frons visible or invisible in dorsal view; maximum width of frons no more than 2x apical width; position of maximum width of frons distinctly dorsad of centre of frontoclypeal suture; median carina complete; lateral carinae slightly elevated. Frontoclypeal suture distinctly semicircular, bent upwards, median part not reaching lower margin of antennal scape. Lateral carinae of anteclypeus well developed. Rostrum just reaching or slightly surpassing hind coxae; subapical segment of rostrum 1.4–1.9 times longer than apical segment.

Thorax: Angle of hind margin of pronotum more or less rectangular. Forewing with crossvein MP-CuA less than half as long as vein MP from M fork to crossvein MP-CuA; Sc+R fused, forming common stem Sc+R, M emerging separately from basal cell or Sc+R+M forming very short common stem; crossvein MP- CuA much shorter than MP from M fork to crossvein and much shorter than crossvein R-M; RP apically bifid; MA apically trifid; 10 apical cells. Hind leg: tibia with 6 apical teeth (innermost tooth smallest and least sclerotised); 1st tarsomere with 7 (rarely 6) apical teeth; 2nd tarsomere with 8 apical teeth and 3 platellae or fine setae.

Female genitalia: Ovipositor elongate, orthopteroid, slightly curved upwards, reaching but not surpassing anal style; 8th sternite medially very long, slightly bent dorsad, posterior margin u-shaped; anal segment square (as long as wide) or rectangular (wider than long) in dorsal view; anal style as long as wide or slightly longer than wide; 9th tergite without wax plates.

Remarks. Dilacreon was previously represented by 16 species from the Australian and Oceanic Region but has not been recorded from Australia itself. Our study has revealed the presence of three species of Dilacreon in Australia. All Australian Dilacreon species share a very similar shape of the pygofer in lateral view, with a deep, rounded incision on the dorsal side leading into a parallelogram-shaped protuberance posterodorsally (13F, 14F, 15F). A similar incision can be found in some New Guinean species of Dilacreon , such as D. (D.) nigricornis Fennah, 1980 , however the posterodorsal protuberance (if present at all) is differently shaped in those species. The thickness and size of the tooth-like appendices situated behind the row of apical teeth on the 2nd tarsomere varies considerably within the genus and even within the species D. (D.) granulinervis . Therefore different terms (fine setae and platellae) are used to describe them although they are most likely of the same evolutionary origin. Dilacreon (D.) akethe and D. (D.) ispi have very large and thick appendices (to which we refer as platellae), in D. (D.) granulinervis some specimens have platellae others possess much more delicate structures (to which we refer as fine setae).