Discodes

August 2018
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1 Head and body black …………..……………………………………………………………………………… sp. 1
1’ Head and body orange ………………………….…………………………….…………………………………… 2

2(1) Funicle without white segments …………………..………………………….. cowboy
2’ Funicle with 1-3 apical segments white ……………………………….……………… 3

3(2) F4-F6 white …………………….………….…………………..……………………. 4
3’ F4 dark……..…………………………………………………………………………… 5

4(3) F1 longer than wide ………………………………………………………..…… sp. 4
4’ F1 quadrate …………………………………………………………….………….. sp. 3

5(3) Scape length about 3x width …………………………………………….. arizonensis
5’ Scape length at least 5x width …………………………………………….…………. 6

6(5) F5-F6 quadrate; head width about 4x frontovertex width at narrowest point …………… sp. 2
6’ F5-F6 length greater than width; head width about 3x frontovertex width at narrowest point ………..…………… sp. 5

 

Sp. 1: Butte, Contra Costa, Lake. Marin, San Benito, Santa Clara, Solano, Stanislaus (EMEC, RLZC, UCD, USNM).
Sp. 2: San Benito, Santa Clara, Stanislaus (RLZC)
Sp. 3: Los Angeles, AZ (RLZC, UCR)
Sp. 4: Marin, Sonoma, Tehama (CSCA, RLZC)
Sp. 5: Lassen, Riverside (UCR)

 

Described Nearctic species and distribution

arizonensis (Howard, 1898): USA (AZ, CA, CO, NM, TX)
cowboy Sugonjaev, 1989: USA (CA, TX)
unicolor (Ashmead, 1888): USA (FL, GA, VA)
yasnoshae Trjapitin & Ruiz Cancino, 2001: MEX (Baja California South)

 

Remarks

Discodes aeneus (Dalman, 1820) was one of a suite of species imported into California from Europe for control of Parthenolecanium corni.  Noyes (2016) recorded it from California, citing Noyes & Hayat (1994), but the latter reference, citing Bartlett, 1978, noted that this species had not established here. Specimens at the USNM of D. unicolor key to sp. 3, but the latter is 1.5x larger, the metasoma length is about equal to the length of the head + mesosoma, and is orange, while for D. unicolor, the metasoma is only as long as the mesosoma, and the color is darker. Specimens of D. yasnoshae key to sp. 2, but in the former F6 is all white and the forewing is infuscate all the way to the tip, while for the latter, F6 is partly or all dark, and the forewing is hyaline at the apex.

 

References

Ashmead, W.H. 1888. Descriptions of new Florida chalcids belonging to the sub-family Encyrtinae. Entomologica Americana 4: 15-17.
Bartlett, B.R. 1978. Coccidae. Pp. 57-74 in Clausen, C.P. (ed.). Introduced parasites and predators of arthropod pests and weeds: a world review. United States Department of Agriculture, Agricultural Handbook 480: 545 pp.
Dalman, J.W. 1820. Försök till Uppställning af Insect-familjen Pteromalini, I synnerhet med afseen de på de I Sverige funne Arter (Fortsättning). Kungliga Svenska Vetenskapsakademiens Handlingar 41: 123-174, 177-182, 340-385.
Howard. L. O. 1898. On some new parasitic insects of the subfamily Encyrtinae. Proceedings of the United States National Museum 21: 231-248.
Noyes, J.S. 2016. Universal Chalcidoidea Database. World Wide Web electronic publication. http://www.nhm.ac.uk/chalcidoids.
Noyes, J.S. & Hayat, M. 1994. Oriental mealybug parasitoids of the Anagyrini (Hymenoptera: Encyrtidae). CAB International, Wallingford, Oxon, UK: 554 pp.
Sugonjaev, E.S. 1989. Notes on taxonomy of encyrtid-wasps (Hymenoptera, Chalcidoidea, Encyrtidae), mainly parasits of soft scale (Homoptera, Coccoidea, Coccidae) in North America and West Indies. Trudy Zoologicheskogo Instituta. Akademiya Nauk SSSR. Leningrad. 191: 90-102.
Trjapitzin, V.A. & Ruiz Cancino, E. 2001. Descripción de una nueva especie del género Discodes Foerster (Hymenoptera: Chalcidoidea: Encyrtidae) de Baja California Sur, Mexico. Biotam 12: 65-70.