Xerococcus Ferris 1921

Xerococcus Ferris 1921: 80. Type species: Xerococcus fouquieriae Ferris 1921, by original designation and monotypy.

Ferris (1921, 1955, 1957) prepared the only detailed description and illustration of this monotypic genus.

Etymology: The generic epithet “ Xerococcus ” is a combination of the Greek words “ xeros ” meaning “dry,” and ” kokkos ” meaning “seed” or “scale insect” and is a masculine noun. The generic epithet is formed because this scale insect occurs in the very xeric desert habitat of Baja California, Mexico.

Field features: According to Ferris (1921: 80) “Occurring beneath the bark scales of the host, imbedded in a considerable amount of amorphous secretion; insects of a bright red color in life.”

Generic diagnosis of adult female: Anal lobes large, strongly protruding; legs represented by small, sclerotized areas; antennae reduced; enlarged setae slightly enlarged; derm with small sclerotized nodules; anal ring complete, without pores, slightly invaginated; multilocular pores restricted to venter, primarily 3-locular pores; macrotubular ducts on both surfaces; microtubular ducts and cruciform pores absent.

Generic diagnosis of second-instar female: Same as adult female except with fewer macrotubular ducts, smaller anal lobes, and fewer multilocular pores, predominantly with 3-locular pores.

Generic diagnosis of first-instar female: Anal lobes small, rounded; legs fully developed, claw with small denticle; antennae each 6-segmented; enlarged setae present along body margin, becoming increasingly shorter and more dome-shaped anteriorly; derm nodules present; multilocular pores near spiracles only, 3-locular; tubular ducts and cruciform pores absent.

Generic diagnosis of second-instar male: anal lobes weakly developed; legs fully developed; dorsal setae in 3 pairs of longitudinal lines; dorsal setae flagellate, weakly capitate; single seta on each tibia; anal ring broad, heavily sclerotized, without separate lateral plates; multilocular pores 3-locular; with dermal nodules; antennae each 7-segmented.

Generic diagnosis of first-instar male: anal lobes weakly developed; dorsal setae in 3 pairs of longitudinal lines; dorsal setae enlarged; single seta on each tibia; anal ring thin, invaginated; multilocular pores normally 3- locular; with dermal nodules.

Notes: Xerococcus is distinctive among eriococcid genera in having: sexually dimorphic first-instar nymphs; and second-instar males with legs and second-instar females with legs reduced.