Updated January 2024
1. Club white, contrasting with funicle …………………………………………..…….………… 2
1’ Club concolorous with funicle ………………………………………………..….…….…….. 14
2(1) Pedicle white …………..………………………………………………….…..….………… 3
2’ Pedicle yellow to brown ….…..…………………………………………….…..….…………. 4
3(2) Wing length no more than 2.5x maximum width; F5 mostly white ………..…….…….… sp1
3’ Wing length 3x maximum width; F5 dark …………………………………..………………. sp2
4(2) Wing hyaline ………………………………………………………………………………… 5
4’ Wing with at least some darkening …………………………………………………………… 6
5(4) Length of frontovertex about 2.0x width ……………………………..…………………… sp3
5’ Length of frontovertex about 1.0x width ………………………………………………..…. sp4
6(4) Forewing fuscous or subfuscous posterior to stigmal vein, completely hyaline distally ….. 7
6’ Forewing centrally fuscous with a more or less distinct paler transverse streak beyond apex of stigmal vein ………………………………………………………………………..…………….. 10
7(6) Linea calva interrupted ……………………………………………..…….……………… sp5
7’ Linea calva not interrupted …………………………………………………………………… 8
8(7) Anterior margin of face narrowly with dark transverse line between bases of mandibles; middle and hind tibiae occasionally with two dark bands ……………………………..… malinus
8’ Anterior margin of face without dark lines between bases of mandibles; middle and hind tibiae without dark bands ….……………………………………………………………….…………… 9
9(8) Ocelli forming right or slightly acute triangle …………………………………..… flavidulus
9’ Ocelli forming extremely acute triangle ……………………………………………………. sp6
10(6) Mesoscutum, axillae and scutellum blackish yellow; lateral borders of mesoscutum white or yellow ………..………………….…………………………………………………….….… 11
10’ Mesoscutum, axillae and scutellum dusky orange-yellow; lateral borders of mesoscutum dark ……………..…………………………………………………………….…………..……….….. 12
11(10) Interior aspect of scape light, except narrowly dark ventrally …………….. maculipennis
11’ Interior aspect of scape dark, except light basally ………………………………………… sp7
12(10) Scutum with 2 dark longitudinal streaks ……….……………………………….…….. sp8
12’ Scutum not so marked …………………………………………………………..…….…… 13
13 Head and thorax dorsally pale orange-yellow, axillary sutures usually not blackish .. angelicus
13’ Head and thorax dorsally deeper shade of orange-yellow mixed with blackish and axillary
sutures brownish black …………………………………………………………………. abstrusus
14(1) Frontovertex as wide as long, or nearly so …………………………….…………… citrinus
14’ Frontovertex length 1.5x width or longer ……………….……………..……………..……. 15
15(14) Extensive dark-brown markings on pronotum, metanotum, propodeum and abdominal tergites; funicular segments moderately transverse, width 1-1.5x length or slightly wider; wings nearly hyaline, forewing sometimes with a faint triangular cloud ……..…….…….. notativentris
15’ Coloration more uniformly yellow, sometimes with dark markings on propodeum and some abdominal tergites, never on mesosoma ………………………………….……………………. 16
16(15) Frontovertex relatively narrow, length 2.0x width, or nearly so ……………………….. 17
16’ Frontovertex wider, length 1.5 to 1.75x width ……………………………………………… 19
17(16) F2-F4 all distinctly transverse ……………………………………….………………… sp9
17’ F2-F4 subquadrate, quadrate or longer than wide ……………..…………………………… 18
18(17) Length scape 5x width; F1-F3 smaller than F4-F5 ……………………….…… antennalis
18’ Length scape 6x width; F2-F5 similar in size ……………………………………………. sp10
19(16) Ocelli forming extremely obtuse triangle, almost in straight line …….……………… sp11
19’ Ocelli forming right or acute triangle ………………………………………………………. 20
20(19) Wings hyaline, or faintly infumate basally ………………………………..…………… 21
20’ Forewing with distinct cloud …………..…………………..……………..………………… 25
21(20) Funicle segments +/- quadrate ………….……………………………………………… 22
21’ Funicle segments +/- transverse ……………………….………………………………….. 24
22(21) F5 wider than long; club length about 2.0x width …………………………………. pallidus
22’ F5 quadrate or longer than wide; club length over 3x width ……..………………………… 23
23 (22) Body yellow; F5 longer than wide …………………………………………………… sp12
23’ Body yellow orange; F5 quadrate ………………………………………………………… sp13
24(21) Ocellar triangle acute ……………………………………………………..………. coccois
24’ Ocellar triangle nearly forming a right angle …………………………………………….. sp14
25(20) Metasoma with two dark crossbands; cloud on forewing smaller, starting distad of speculum …………………………………………………………………..…….…… californicus
25’ Metasoma uniformly yellow; cloud on forewing large, starting proximal of speculum ……. 26
26(25) Frontovertex length 1.75x width …………………………….…….…..………….. texanus
26’ Frontovertex length 1.5x width ……………………………………………………….……. 27
27(26) Mesopleuron markedly darker than scutum ……………………………….…….…… sp15
27’ Mesopleuron concolorous with scutum ………………………………………………….… 28
28(27) Length of club 2.5x width ………………………..…………………………… fasciipennis
28’ Length of club 3.0x width …….……………………………………….……………..……. 29
29(28) Funicle segments wider than long ……………………………………………..…….. sp16
29’ Funicle segments quadrate ………………….………………..….………………………. sp17
Sp. 1 Riverside (UCRC)
Sp. 2 Inyo (UCRC), Lassen (RLZC)
Sp. 3 Contra Costa, Lassen, San Benito, Santa Clara, Stanislaus (RLZC & UCDC); Orange
(UCRC); insectary reared (EMEC); San Luis Obispo
Sp. 4 Imperial (UCDC)
Sp. 5 Lassen (RLZC)
Sp. 6 Tulare (UCRC)
Sp. 7 Alameda, Contra Costa, Stanislaus (RLZC); Riverside (UCRC)
Sp. 8 Orange (UCRC)
Sp. 9 Los Angeles (RLZC)
Sp. 10 Contra Costa, Marin, Stanislaus (RLZC); Riverside (UCRC)
Sp. 11 Marin (RLZC)
Sp. 12 Modoc (RLZC)
Sp. 13 Alameda, Stanislaus (RLZC)
Sp. 14 Contra Costa, Marin, San Joaquin, Stanislaus (RLZC); Riverside (UCRC); Santa Barbara
Sp. 15 Contra Costa, Marin, Santa Clara (RLZC); Riverside (UCRC)
Sp. 16 Lassen (RLZC); Riverside (UCRC)
Sp. 17 Stanislaus (RLZC)
Described Nearctic species and distribution
abstrusus (Gahan, 1946): USA (CA, VA)
alveolatifrons (Gahan, 1946): USA (NJ)
angelicus (Howard, 1898): USA (CA, WA); CAN (PQ)
antennalis Rosen, 1969: USA (CA)
californicus Rosen, 1969: USA (CA)
citrinus (Howard, 1898): USA (CA, NV, OH)
coccois Smith, 1880: USA (CA, GA, IL, MA, NJ, OH, PE); MEX (MX)
debachi Rosen, 1981: MEX (SO)
debilis Timberlake, 1924: MEX (MO)
erii Timberlake, 1916: USA (UT)
fasciipennis Timberlake, 1918: USA (CA)
flavidulus (Brethes, 1916): Introduced from Chile into USA (CA)
graminicola (Timberlake, 1916): USA (NM, UT)
gutierreziae Timberlake, 1916: USA (NM)
limatulus (Gahan, 1946): USA (MD)
maculipennis (Mercet, 1923): Introduced from European stock in New Zealand into quarantine USA (CA), but not released.
malinus (Gahan, 1946): Introduced from Japan into USA (CA, CN, DE, MI, MO, NJ, OH, VA, WV); CAN (ON)
meracus (Gahan, 1946): USA (VA)
meritorius (Gahan, 1946): USA (MD, VA)
mundus (Gahan, 1946): USA (FL, GA, LA, TX, VA); MEX
notativentris (Girault, 1917): USA (CA, CN, MO, VA, VT, WA); MEX (BC)
pallidus Timberlake, 1918: USA (CA)
papayae Noyes & Schauff, 2003: Introduced from Mexico into USA (FL)
prosopidis (Timberlake, 1916): USA (NM)
texanus (Howard, 1898): USA (TX); MEX (DU); introduced from Mexico into USA (CA)
utilis (Timberlake, 1923): MEX (SN)
websteri (Timberlake, 1916): USA (IL, IN, WA)
Remarks
Gahan (1946) provided a key to the 16 described species (worldwide) then known of Pseudaphycus Clausen, and Rosen (1969) did the same for the 13 described species (worldwide) of Acerophagus Smith. Several authors commented that these taxa were closely related, and in 2008 Trjapitzin formally synonymized Pseudaphycus under Acerophagus. Just prior to this, Daane et al (2008) provided a key to the Pseudaphycus species (plus one Acerophagus species) likely to be found in North American vineyards and tree fruit orchards.
As the basis for this key, I combined those of Gahan and Rosen, disregarding the taxa not recorded from California, and then folded in the key characters from Daane et al. to include A. flavidulus, which they reported as recently established. I then added in couplets to account for an additional 17 taxa that did not exactly match the 13 described Acerophagus species recorded from the state. Several of these additional taxa are known from only one or two specimens, and many are old, and not in good condition. Unfortunately, my key heavily relies upon the infumation of the forewing, but I suspect this is a character that varies with the age of the specimen, and how the specimen was prepared. My bias in preparing this key tended towards that of a splitter, and several of my unnamed taxa may ultimately prove to be simply variants of other species.
Acerophagus maculipennis was originally described from the Palearctic region, but Charles (2010) argues it is likely it has a neotropical origin. European specimens were introduced into New Zealand, and stock from that population were brought into quarantine in California in 2006, but never released. Nevertheless, this species was reared in San Luis Obispo in 2007, and another specimen which seems referable to this species was reared from a mealybug in a greenhouse in Santa Clara County in 1981.
Acerophagus mundus (Gahan) was imported into California in a 1944 biocontrol program against Pseudococcus longispinus – although the parasitoid was able to attack the mealybug in the lab, it failed to establish here (Bartlett, 1978). This species apparently is native to Louisiana, and may have been spread throughout the region via biocontrol programs (Gahan, 1946; Bartlett, 1978). Acerophagus perdignus (Compere & Zinna, 1955) was imported from Eritrea in 1953 in a biocontrol program against Planococcus citri, and released in San Diego and Santa Barbara Counties (Clausen, 1955). Gordh (1979) noted it was “possibly established”, but I have found no evidence that it was ever recovered. de Santis (1979) listed Pseudaphycus prosopidis Timberlake, 1916 from “Mexico”, but I have been unable to find any supporting evidence for this listing. In the OD, Timberlake noted (page 572) the collecting locale as “Mesilla, New Mexico”, wherein “New” and “Mexico” appeared on different lines, and perhaps de Santis misread this as a record for the country Mexico. Daane et al. (2008) reported the establishment of A. flavidulus in California.
In my California checklist (Zuparko 2015), I reported A. abstrusus from Imperial County. I was unable to confirm this, but I did find a specimen attributable to this species from San Mateo County (RLZC). In that same paper I also reproted a species “meracus or near” from Tulare County from the UC Riverside collection – this is represented in the key as “sp. J2”.
References
Bartlett, B.R. 1978a. Pseudococcidae. Pp. 137-170. 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.
Brèthes, J. 1916. Hyménoptères parasites de l’Amérique meridionale. Anales del Museo Nacional de Historia Natural de Buenos Aires 27: 401-430.
Charles, J.G. 2010. Using parasitoids to infer a native range for the obscure mealybug, Pseudococcus viburni, in South America. BioControl 56: 155-161.
Clausen, C.P. 1955. Releases of recently imported insect parasites and predators in California, 1952-53. The Pan-Pacific Entomologist 31: 77-79.
Compere, H. & G. Zinna. 1955. Tre nuovi generi e cinque nuove especie di Encyrtidae. Bollettino del Laboratoria di Entomologia Agraria ‘Filippo Silvestri’, Portici 14: 94-116.
Daane, K.M., M.L. Coper, S.V. Triapitsyn, J.W. Andrews Jr. & R. Ripa. 2008. Parasitoids of the obscure mealybug, Pseudococcus viburni (Hem.: Pseudococcidae) in California: establishment of Pseudaphycus flavidulus (Hym.: Encyrtidae) and discussion of related parasitoid species. Biocontrol Science and Technology 18: 43-57.
de Santis, L. 1979. Catálogo de los himenópteros calcidoeos de América al Sur de los Estados Unidos. Publicación Especial Comisión de Investigaciones Científicas Provincia de Buenos Aires, La Plata, 488 pp.
Gahan, A.B.1946. Eight new species of chalcid-flies of the genus Pseudaphycus Clausen, with a key to the species. Proceedings of the United States National Museum 96: 311-327.
Girault, A.A. 1917. Descriptiones Hymenopterorum Chalcidoidicarum variorum cum observationibus III. Private publication, Glenndale, Maryland: 10 pp.
Gordh, G. 1979. Family Encyrtidae. Pp. 890-967 in Krombein, K.V., P.D. Hurd, Jr., D.R. Smith & B.D. Burks (eds.). Catalog of Hymenoptera in America North of Mexico. 1 Symphyta and Apocrita (Parasitica). Smithsonian Institution Press, Washington, D.C.: 1198 pp.
Howard, L.O. 1898. On some new parasitic insects of the subfamily Encyrtinae. Proceedings of the United States National Museum 21: 231-248.
Mercet, R.G. 1923. Encírtidos de Canarias. Boletin de la Real Sociedad Español de Historia Natural. 23: 138-145.
Noyes, J.S. & Schauff, M.E. 2003. New Encyrtidae (Hymenoptera) from papaya mealybug (Paracoccus marginatus Williams and Granara de Willink) (Hemiptera: Sternorrhyncha: Pseudococcidae). Proceedings of the Entomological Society of Washington 105: 180-185.
Rosen, D. 1969. A systematic study of the genus Acerophagus E. Smith with descriptions of new species (Hymenoptera: Encyrtidae). Hilgardia 40: 41-72.
Rosen, D. 1981. A new species of Pseudaphycus [Hym.: Encyrtidae], with notes on the angelicus group. Entomophaga 26: 251-263.
Smith, E.A. 1880. Biological and other notes on Pseudococcus aceris. North American Entomologist 1: 73-87.
Timberlake, P.H. 1916. Revision of the parasitic Hymenopterous insects of the genus Aphycus Mayr, with notice of some related genera. Proceedings of the United States National Museum 50: 561-640.
Timberlake, P.H. 1918. New genera and species of Encyrtidae from California parasitic in mealybugs (Hymenoptera). University of California Publications in Entomology 1: 347-367.
Timberlake, P.H. 1923. Descriptions of two new species of Encyrtidae from Mexico reared from Mealy-bugs (Hym., Chalcidoidea). Proceedings of the Hawaiian Entomological Society 5: 323-333.
Timberlake, P.H. 1924. Descriptions of new chalcid-flies from Hawaii and Mexico (Hymenoptera). Proceedings of the Hawaiian Entomological Society 5: 395-417.
Trjapitzin, V.A. 2008. A review of encyrtid wasps (Hymenoptera, Chalcidoidea, Encyrtidae) of Macaronesia. Entomologicheskoe Obozrenie 87: 166-184.
Zuparko, R.L. 2015. Annotated checklist of California Encyrtidae (Hymenoptera). Zootaxa 4017: 1-126.