Phyllococcus Ehrhorn, 1916

Percy, Diana M., Watson, Gillian W. & Hodgson, Chris J., 2024, The endemic Hawaiian mealybug genus Phyllococcus Ehrhorn, 1916 (Hemiptera: Coccomorpha: Pseudococcidae): redescription of the type species and description of a new species on an endangered host plant, Cryptocarya mannii (Lauraceae), Zootaxa 5447 (3), pp. 355-372 : 356-357

Genus Phyllococcus Ehrhorn, 1916

Type species: Cissococcus? oahuensis Ehrhorn 1912: 149 .

Generic diagnosis, based on adult female morphology (modified from Ferris in Zimmerman 1948: 159‒160). Phyllococcus is a genus of gall-inducing mealybugs that form deep pit galls in the leaves of their hosts. More than half of body composed of head and thorax. Posterior abdominal segments strongly sclerotised dorsally to form a broadly oval shield, used to close gall opening. Sclerotised shield composed of dorsum of abdominal segments VII, VI and V ( Ph. oahuensis ) or VII–III ( Ph. cryptocaryae ); venter of these segments membranous. Posterior part of shield formed from flattened, strongly sclerotised anal lobes, each with spinose cerarian setae. Anal ring concealed between bases of anal lobes (in Ph. oahuensis ) or at end of short anal tube ( Ph. cryptocaryae ); anal ring bearing 6 quite long setae, and with 2 rows of small pores. Vulva large and distinct. Antennae each 6 or 7 segmented; both apical and preapical segments with fleshy setae. Mouthparts typical for mealybugs. Legs either quite short and stout ( Ph. oahuensis ) or longer and slender ( Ph. cryptocaryae ); each trochanter with 2 campaniform sensilla on each side; tarsal and claw digitules capitate; claws each without a denticle; hind legs with translucent pores on femur and tibia in both species (mostly on dorsolateral and dorsal surfaces), also on trochanter and tarsus in Ph. oahuensis . Anterior dorsal ostioles present but poorly developed; posterior ostioles absent. Cerarii represented only by short, conical spinose setae on each anal lobe, either with spinose setae along entire posterior margin ( Ph. cryptocaryae ) or restricted to 2 on apex of each anal lobe ( Ph. oahuensis ). Circulus absent. Oral collar tubular ducts apparently absent in Ph. oahuensis ; in Ph. cryptocaryae , these ducts present along posterior margins of segments in sclerotised shield but absent elsewhere. Setae sparse on head and thorax on both dorsum and venter but either becoming very abundant and longer on ventral abdomen, particularly posteriorly where more spinose ( Ph. cryptocaryae ), or sparse on abdomen and not spinose ( Ph. oahuensis ). Trilocular pores present on both dorsum and venter of head and thorax but absent from dorsal shield and both surfaces of anal lobes in both species, and from dorsum and venter of abdominal segments III‒VII in Ph. oahuensis . Simple pores present wherever trilocular pores present, very sparse.

Comments. Ehrhorn (1912), in his original description of the type species, placed it tentatively in Cissococcus Cockerell , which he indicated by a question mark after the genus name. Cissococcus belongs to family Coccidae and is found only in South Africa ( Hodgson et al. 2011). Beardsley (1984) also recorded Ph. oahuensis on Urera sandwicensis Wedd. (now Touchardia sandwicensis (Wedd.)) ( POWO 2023; Wells et al. 2021) on Oahu, and Zimmerman (1948) noted a collection from Lanai, but no recent collections of Ph. oahuensis have been made from these islands and it may be that these populations are now locally extirpated (Janis Matsunaga, Hawai’i Department of Agriculture, pers. comm.). With the addition of the new species described below, the genus Phyllococcus now contains two endemic species from the Hawaiian Islands.