Genus Idiosystatus Berg, 1879

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Family Delphacidae Leach, 1815

Subfamily Asiracinae Motschulsky 1863: 108.

Tribe Idiosystanini Emeljanov, 1995

Genus Idiosystatus Berg, 1879: 137. [1883: 231]

Distribution: Temperate South America.

Distribution of Idiosystatus from FLOW

Distribution of Idiosystatus from FLOW (31 Jan. 2020)

Synonyms: None.

Type species (in original combination): Delphax acutiuscula Spinola, 1852: 258.

Recognized species

There are five recognized species currently placed in this genus [Metcalf 1943: 50].

Idiosystatus  acutiusculus (Spinola, 1852: 258) [Metcalf 1943: 51] – Argentina, Chile
= Delphax acutiuscula Spinola, 1852: 258.
= Idiosystatus acutiusculus (Spinola, 1852), comb. by Berg, 1879: 138, 1883: 231.
Idiosystatus  australis Fennah, 1969: 52 – Argentina
Idiosystatus  fuscoirroratus (Spinola, 1852: 260) – Chile
= Delphax fuscoirrorata Spinola, 1852: 260.
= Delphax vittata Spinola, 1852: 260; syn. by Fennah 1969: 50.
= Liburnia fuscoirrorata (Spinola, 1852); comb. by Berg 1881: 266.
= Megamelus fuscoirroratus (Spinola, 1852); comb. by Crawford 1914: 682.
= Delphacodes fuscoirrorata (Spinola, 1852); comb. by Muir 1926: 38.
= Idiosystatus  fuscoirroratus (Spinola, 1852); comb. by Fennah 1950: 250.
Idiosystatus  gubernator Fennah, 1969: 48 – Argentina
Idiosystatus  longifrons Fennah, 1969: 51- Chile

Plant associations

Idiosystatus acutiusculusLeptocarpus sp. (Poales, Restionaceae) (Fennah 1965: 150).

Idiosystatus acutiusculusSchoenoplectus californicus (C.A. Mey.) Soják (Cyperaceae).

Host from Fennah (1965) via FLOW.  Campodonico (2017) collected Idiosystatus from Schoenoplectus  (as above), and Idiosystatus fuscoirroratus  from a sedge dominated landscape; he has argued that all Idiosystanini are sedge specialists (which seems likely given current evidence).

Plant names linked to USDA PLANTS or Tropicos.

Economic Importance: Limited.


This genus revised by Fennah (1969).  Species can be common and I have examined good series from sweep and vacuum samples from Argentina and Chile.

Somewhat flattened with paired carinae on the frons and 5 carinae on the mesonotum.  Most similar to Pentagramma, but that genus tends to be green (not earth toned).

Key to species of Idiosystatus modified from Fennah (1969)
1. Pronotum with median carina double; frons with a broad yellowish fascia across middle … fuscoirrotatus (Blanchard)
1′.- Pronotum with median carina simple; frons with at most only a narrow fascia, not yellow … 2

2. Vertex more than 1.5 times as long in middle as broad at base … 3
2′.- Vertex at most scarcely longer in middle than broad at base … 4

3 Eye with 2 concavities on lower margin, the anterior smaller than the posterior; vertex not twice as long in middle as broad at base; mesonotum with 5 carinae … acutiusculus (Spinola)
3′.- Eye with a single concavity on lower margin; vertex twice as long in middle as broad at base; mesonotum with 4 carinae … longifrons Fennah

4. Frons slightly wider at base than at apex; genital styles of male meeting only at base … australis Fennah
4′- Frons as wide at base as at apex; genital styles of male apposed in basal two-fifths … gubernator Fennah

Idiosystatus  acutiusculus (Photos by Kimberley Shropshire, Department of Entomology, University of Delaware)

Idiosystatus acutiusculus

Idiosystatus acutiusculus

Idiosystatus acutiusculus

Idiosystatus acutiusculus

Idiosystatus acutiusculus

Idiosystatus acutiusculus

Idiosystatus acutiusculus from Fennah 1965: 250.

Idiosystatus gubernator From Fennah 1969

Idiosystatus gubernator From Fennah 1969


Idiosystatus australis

Idiosystatus australis from Fennah 1969

Idiosystatus acutisculus

Idiosystatus acutisculus from Fennah 1969


Idiosystatus gubernator Fennah from Fennah 1969

Idiosystatus longifrons from Fennah 1969

Online Resources

BOLD (link to subfamily).
Discover Life.
3i Interactive Keys and Taxonomic Databases.
MNHN (link to syntype record).
SCAN Symbiota (no data to speak of).

Molecular resources

None. genus not present in BOLD (link to subfamily); or Genbank.

Selected references

Barringer, L. E. and C. R. Bartlett. 2011. A review of New World Asiracinae (Hemiptera: Auchenorrhyncha: Delphacidae) with five new taxa. Cicadina 12: 7-39.

Berg, C. 1879a. Hemiptera Argentina (Continuacion). Hemiptera Homoptera Latr. Anales de la Sociedad Cientifica Argentina 8: 135-144.

Berg, C. 1881b. Sinonimia y descripcion de algunos Hemípteros de Chile, del Brasil y de Bolivia. Anales de la Sociedad Científica Argentina 12: 259-272.

Berg, C. 1883b. Addenda et Emendanda ad Hemiptera Argentina (Continuatio.) Anales de la Sociedad Cientifica Argentina 16: 231-241.

Breddin, G. 1897. Hemipteren. Ergebnisse der Hamburger Magalhaensischen Sammelreise. Herausgegebn vom der Hamburger naturhistorisches Museum 2(4): 1-36. [see p. 31]

Campodonico, J. F. 2017. A new species of Pentagramma Van Duzee (Hemiptera: Delphacidae: Asiracinae) from Chile, with notes on the host relations of the Idiosystatini Emeljanov. Zootaxa 4291(3). doi:

Crawford, D. L. 1914a. A contribution toward a monograph of the homopterous insects of the family Delphacidae of North and South America. Proceedings of the United States National Museum 46: 557-640, plus 6 plates. [listed p. 632]

Emeljanov, A. F. 1996. On the question of the classification and phylogeny of the Delphacidae (Homoptera, Cicadina), with reference to larval characters. Entomological Review 75(9):134-150. [Translated from Russian in Entomologicheskoe Obozrenie 74: 780-794.]

Fennah, R. G. 1965. Fulgoroidea from Southern Chile (Hemiptera). Bulletin of the British Museum (Natural History) Entomology 17: 233-272.

Fennah, R. G. 1969. A revision of the Idiosystatus Berg (Homoptera: Fulgoroidea, Delphacid). Proceedings of the Royal Entomological Society of London 38(3-4): 47-52.

Fennah, R.G. 1979 Tribal classification of Asiracine Delphacidae (Homoptera: Fulgoroidea). Entomologist’s Record (I/V./79): 116. [genus noted]

Leach, W. E. 1815a. Entomology. The Edinburg encyclopedia; conducted by David Brewster 9: 57-172. (family Delphacidae page 125).

Metcalf, Z. P. 1943. General Catalogue of the Hemiptera. Fascicle IV, Fulgoroidea, Part 3, Araeopidae (Delphacidae). Smith College, Northhampton, Massachusetts. [p. 50]

De Motschulsky, V. I. 1863. Essai d’un catalogue des insectes de l’ile de Ceylan. Bulletin de la Société Impériale des Naturalistes de Moscou 36: 1-153. (Delphacidae p. 108)

Muir, F.A.G. 1915b-e. A contribution towards the taxonomy of the Delphacidae. Canadian Entomologist 47: 208-212 (Muir 1915b), 261-270 (c), 296-302 (d), 317-320 (e). [genus noted p. 212, 264)

Spinola, M. 1852a. Tribu IV.-Hipocefalocera. Gay’s Historia fisica y politica de Chile. Paris. 7: 238-305, plate 3. (whole volume, courtesy Memoria Chilena).

USDA APHIS PPQ. 1982. List of intercepted plant pests, Fiscal years 1980 and 1981. USDA APHIS PPQ, Hyattsville, MD. APHIS 82-8. vi+476 pp. [listed p. 166]

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