Formicococcus Takahashi 1928

Tanaka, Hirotaka, 2022, A taxonomic study of three mealybug species (Hemiptera: Coccomorpha: Pseudococcidae) infesting dwarf bamboo in Japan, with description of a new species, Zootaxa 5178 (4), pp. 334-346 : 335-336

Genus Formicococcus Takahashi 1928

Formicococcus Takahashi 1928: 253 . Type species: Formicococcus cinnamomi Takahashi 1928 .

Planococcoides Ezzat & McConnell 1956: 53 . Type species: Pseudococcus njalensis Laing 1929 .

Drymococcus Borchsenius 1962: 221 . Type species: Drymococcus rhizophilus Borchsenius 1962 .

Indococcus Ali 1967: 35 . Type species: Indococcus pipalae Ali 1967 .

Formicoccus Tang 1984: 125 ; Tang et al. 1992: 5 (misspelling).

Genus diagnosis (adapted and modified from Williams 2004). Body of adult female with anal lobe bars present. Cerarii numbering 3–18 pairs; sometimes cerarian setae present in tufts, associated with a group of trilocular pores; auxiliary setae present or absent. Anal lobe cerarii each bearing 2 or more cerarian setae, each seta either conical or with a flagellate tip. Anterior abdominal cerarii each usually containing more than 2 conical or flagellate setae; if numbering only 2, then auxiliary setae often present also. Antennae each with 6–8 segments. Legs well developed; hind leg with translucent pores on coxa and often on tibia, sometimes present also on femur; often tibia + tarsus shorter than trochanter + femur. Claw stout, often curved, without a denticle.

Dorsal setae often short and stiff, slender or conical, but sometimes long and flagellate, rarely stout. Cisanal and obanal setae always conspicuous. Ostioles prominent. Circulus present or absent. Anal ring normal, bearing 6 setae; sometimes with multiple setae present but if so, then usually 6 setae longer than others. Anal ring position either at apex of abdomen or slightly dorsal. Multilocular disc pores present, on venter of abdomen at least. Oral rim tubular ducts absent. Oral collar tubular ducts present, at least on venter of abdomen, sometimes also around margins of head and thorax and on dorsal surface. Microducts sometimes present.

Remarks. The definition of the genus Formicococcus has been extended here to include the Japanese species, Formicococcus bambusiphilus ( Takahashi 1958) , F. kawaii sp. nov. and F. yoshinoi Tanaka in Tanaka et al. 2021. Formicococcus is quite similar to Planococcus Ferris 1950 and Crisicoccus Ferris 1950 , so it may be difficult to distinguish these genera. Further morphological and molecular phylogenetic study of these three genera is greatly needed.

Key to the mealybug genera with anal lobe bars and without oral rim ducts found in Asia (adapted and modified from Williams 2004)

1(0) Anal lobe bar present on venter of anal lobe and oral rim ducts extremely rare or absent from derm.................... 2

– Anal lobe bar absent from venter of anal lobe, or oral rim ducts present on derm in every specimen...................................................................................... other genera and species of Pseudococcidae

2(1) Anal lobe cerarii each located on a well-developed, large, oval, heavily sclerotized plate................................................................................................... Dysmicoccus wistariae ( Green 1923)

– Anal lobe cerarii not located on large, oval, heavily sclerotized plates........................................... 3

3(2) Some or all abdominal cerarii each bearing more than 2 cerarian setae (note: Formicococcus lingnani Ferris 1954 occasionally lacks anal lobe bars)......................................................... Formicococcus Takahashi 1928

– All abdominal cerarii each bearing only 2 cerarian setae...................................................... 4

4(3) Cerarii numbering 18 pairs........................................................... Planococcus Ferris 1950

– Cerarii numbering 0–17 pairs, with preocular pair (C 2) absent............................... Crisicoccus Ferris 1950

Key to adult females of Formicococcus species in Japan

1(0) Body broadly oval. Dorsal tubular ducts absent............................. F. yoshinoi Tanaka in Tanaka et al. 2021

– Body elongate oval. Dorsal tubular ducts present............................................................ 2

2(1) Cerarii numbering 5‒7 pairs. Circulus oval to quadrate....... F. bambusiphilus ( Takahashi 1958) stat. rev. and comb. nov.

– Cerarii numbering 18 pairs. Circulus dumbbell shaped................................... F. kawaii Tanaka sp. nov.