Genus Phenacoccus Cockerell 1893

Phenacoccus Cockerell 1893: 318 .

Type species: Pseudococcus aceris Signoret 1875 .

Paroudablis Cockerell 1900: 87 [as a subgenus of Phenacoccus]. Type species: Boisduvalia piceae Löw 1883 .

Bouhelia Balachowsky 1938: 37 . Type species: Bouhelia maroccana Balachowsky 1938 .

Peukinococcus Šulc 1944: 2 . Type species: Boisduvalia piceae Löw 1883 .

Caulococcus Borchsenius 1960: 47 . Type species: Phenacoccus angustatus Borchsenius 1949

Densispina Ter-Grigorian 1964: 861 . Type species: Densispina graminea Ter-Grigorian 1964

Birendracoccus Ali 1975: 279 . Type species: Dactylopius saccharifolii Green 1908

Giraudia Goux 1989: 292 . Type species: Giraudia danielaferreroae Goux 1989 .

Gouixia Koçak & Kemal 2009: 1. Replacement name for Giraudia Goux, 1989

Diagnosis (adapted and slightly modified from Williams 2004). Body usually broadly oval; anal lobes developed, at least moderately, sometimes with anal lobe bar. Antennae mostly each with 9 segments, sometimes reduced to 6 to 8 segments. Legs well developed, usually slender, often with denticle on claw. Tarsal digitules present, flagellate. Translucent pores absent on hind coxae, sometimes present on hind femur and tibia, hind coxae often with oblique lines or narrow grooves. Cerarii numbering 1–18 pairs, always with 1 pair present on anal lobes. Each cerarius with 2 or numerous enlarged conical to lanceolate setae with trilocular pores, often on membranous or sclerotised areas that protrude from surface of derm. Dorsal cerarii sometimes present. Dorsal setae present, usually short and lanceolate, sometimes with 1 or more trilocular pores near larger setal collars. Circulus usually present between abdominal segments III and IV, often oval or transversely narrow. Sometimes with lateral extensions and elevated from surface of derm; occasionally 2–5 cerarii present. Multilocular disc pores usually present, rarely absent entirely, often distributed on venter in transverse segmental rows, at least on abdomen; sometimes occurring in transverse rows on dorsum. Quinquelocular pores often present on venter, sometimes represented by only a few next to mouthparts; occasionally present on dorsum also. Oral collar tubular ducts often present on dorsum and venter, sometimes numerous.

Remarks. The molecular phylogenetic analysis on mealybugs conducted in this study showed that, like Dysmicoccus, the genus Phenacoccus is also not a simple monophyletic group (Fig. 1), so the current definition of the genus is probably arbitrary. There is a great need for further molecular and morphological studies of the genus.

Key to adult females of Phenacoccus species in Japan

1(0) Venter without quinquelocular pores...................................................................... 2

- Venter with quinquelocular pores......................................................................... 3

2(1) Multilocular disc pores restricted to bands across posterior margin of each abdominal segment and very rarely present on submarginal areas of abdomen........................................................... P. solani Ferris 1918

- Multilocular disc pores scattered across full depth of segment VII between anterior to posterior margins, small clusters also often present submarginally on some abdominal segments................................ P. solenopsis Tinsley 1898

3(1) Venter with 2 or more circuli............................................................................ 4

- Venter with 0 or 1 circulus.............................................................................. 5

4(3) Venter with 2 or 3 circuli. Antennae each ca. 450–600 µm long.............................. P. azaleae Kuwana 1914

- Venter with 3‒5 circuli (usually 4). Antennae each ca. 600–700 µm long................... P. pergandei Cockerell 1896

5(3) Cerarii numbering fewer than 12 pairs, present on head and posterior abdominal segments only. Circulus always absent.................................................................................... P. interruptus Green 1923

- Cerarii numbering more than 13 pairs, not confined on head and posterior abdominal segments. Circulus present or absent... ................................................................................................... 6

6(5) Dorsum with oral collar tubular ducts forming transverse rows................................................. 7

- Dorsum without oral collar tubular ducts on medial to submedial area of dorsum................................... 8

7(6) Dorsal abdominal segments with a considerable number of multilocular disc pores on medial to submedial areas of metathorax and abdomen.................................................................... P. madeirensis Green 1923

- Dorsum with multilocular disc pores absent or very few.................................. P. avenae Borchsenius 1949

8(6) A considerable number of dorsal setae each associated with 1 or 2 trilocular pores next to setal collar. Venter with quinquelocular pores on abdominal segments IV–VII................................................. P. parvus Morrison, 1924

- Dorsal setae not associated with trilocular pores. Venter of abdominal segments IV–VII without quinquelocular pores..................................................................................... P. miruku Tanaka sp. nov.