Mesocallis Matsumura, 1919

Mesocallis Matsumura 1919: 103. Type species: Myzocallis sawashibae Matsumura, 1917; by original designation.

Mesocallis Subgenus Mesocallis Matsumura 1919: 103

Neocallis Synonym: Neocallis Matsumura 1919: 104.

Nippochaitophorus Synonym: Nippochaitophorus Takahashi 1961: 247.

Paratinocallis Subgenus Paratinocallis Higuchi 1972: 30. Type species: Paratinocallis corylicola Higuchi,1972; by original designation. Given subgenus status by Quednau (2003: 20).

Mesocallis Matsumura: Higuchi 1972: 22; Raychaudhuri et al. 1980: 291; Ghosh and Quednau 1990: 114; Quednau 2003: 19; Qiao et al. 2005: 194; Lee et al. 2018: 3.

Generic diagnosis.

In alatae, eyes with ocular tubercles. Antennae 6-segmented, processus terminalis 0.80-1.20 × as long as the base of the segment. Ultimate rostral segment with 2-16 accessory setae. First tarsal segments with five to seven ventral setae and two dorsal setae. Empodial setae flabellate. Siphunculi truncated, without flange, without any setae surrounding at base. Cauda knobbed. Anal plate bilobed. Gonapophyses fused, with eight gonosetae. In apterae, nymphs and embryo, dorsal body setae with spinulose shafts, and round knobs at apex. Abdominal tergites I-IV with one pair of marginal setae in subgenus Mesocallis, or two or three pairs of marginal setae in subgenus Paratinocallis . Compound eye of apterous morph often smaller and with fewer facets than in the alate morph, and inner setae of antennal segment III inconspicuous. Apterae with 5- or 6-segmented antennae, dorsal setae of tibiae similar to other tibial setae in subgenus Mesocallis, or strongly differentiated from other tibial setae in subgenus Paratinocallis; first tarsal segments with five ventral setae, without dorsal setae. In embryo, dorsal body setae capitate at apex; spinal setae of metanotum and tergites I, III, and V short or minute, pleural setae absent. Viviparae alate and apterous in some species.

Distribution.

China, Japan, Korea, and India.

Host plants.

Alnus, Carpinus, Corylus, and Ostrya ( Betulaceae), and Platycarya ( Juglandaceae).

Comments.

Of the known Myzocallis species, most infest plants of Betulaceae . Two species ( Myzocallis obtusirostris and Mesocallis taoi) are primarily associated with Alnus; and three species ( Mesocallis corylicola, Myzocallis occulta, and Myzocallis yunnanensis) are associated with Corylus . Myzocallis carpinicola is recorded only on Carpinus . Additionally, M. alnicola infests both Alnus and Corylus, and M. sawashibae occurs on both Carpinus and Corylus (Lee et al. 2018). Only M. pteleae infests plants in several different genera of Betulaceae ( Alnus, Betula, Corylus, Carpinus, and Ostrya) (Holman 2009). So, Mesocallis species have distinct host specialization. However, the new species, M. platycaryae Qiao was found on Platycarya ( Juglandaceae). All species occur only in East Asia and are endemic to this region.